Title: Chemical Consummation
Rating: T
Disclaimer: Not mine. Don't sue.
Dedication: This one is dedicated to saganamidreams for giving me way too much praise, betaing a heck of a lot of writing (You guys haven't seen the 22 chapter epic yet) and for managing to do it about ten seconds flat.
Author's Note Well, this is the end of the Chemistry fic series. Except for that other one I just wrote…

The first four can be found her:
Subtle Chemistry
Chemical Symmetry
The Sweetness Triangle
Dynamic Chemistry

Also, there's an accompanying piece called the Elementals at my livejournal, user name: doonarose
A fortnight and he'd hardly dared look at her. Fourteen days that felt like an eternity to both of them, leaving him hollow, her angry and both of them uncomfortable. But it wasn't as though she could be angry at him, he hadn't done anything wrong; if anything he'd done something amazingly right and she'd been the one to screw it all up. Because, god help her, his lips had felt like the most heavenly sin; right and wrong, good and bad and yet just perfectly sublime.

The actual physical feeling of it was only a small fraction of the entire sensation, countless boys had kissed her neck, but never like this. This blew her mind with the fact that, just below the surface, she could sense his desperation and intensity. It was leaking through, into his actions, his breathing and, had she been able to see, his expressions. She'd turned her head, wanting to feel his lips on hers, to force him, trick him or tempt him into letting the intensity free and then she'd made him stop.

Sitting up in her bed, she glanced to the clock, just past three in the afternoon. She sighed and let her head fall back onto the wall with a thud. She would have cried with the frustration of it except she'd already done that many times and not once had it worked.

This was a nightmare come true; she was stuck traveling with the Doctor, having admitted her feelings and then realized he didn't feel the same way. That was her nightmare, and that was what it felt like and yet she knew perfectly well how he felt; exactly the same as her. He'd made it plain and then she'd blown it all up.

The day after, she'd tried to tell him, but he'd refused to listen, thinking she was just trying to apologize or make excuses. As he'd turned away and directed the TARDIS into the middle of World War IV, she'd seen the hurt in his eyes and stopped herself from pushing the issue.

Purposely choosing three successive destinations filled with noise and action, he'd found little reason to talk to her about anything other than the problems in front of them; he'd refused to hold her hand, and she noticed that every time she got too close he winced like he'd been burnt.

Rose banged her head against the wall again, clenching her teeth before opening her eyes and staring at herself in the mirror. Why had she stopped him? I don't…What did that even mean? I don't want to? I don't think we should? I don't think we're ready? All wrong. She sighed and grabbed the nearest book: "Introduction to Chemical Experimentation II".

A fortnight with no one to talk to was a long time and she'd managed to pick up a lot of chemistry from the books she'd found. She still had no idea why she was doing it, why she'd gone to the library with the sole intent of teaching herself some of the Doctor's art; it didn't help and it didn't feel good, it felt bittersweet and futile. Chemistry was good, it was interesting, but only when it was their chemistry.

Flipping to where she'd last dog-eared the text, she read the new chapter title, "False positives and negatives," and the introduction that followed.

Her eyes widened, and in ten minutes she'd finished the entire chapter, had hauled herself out of the bed for the first time that day and was pulling on her clothes. The phosphates had been a false positive. She'd asked him about the results of their experiment as soon as they'd returned from World War IV. The aim had been, once again, to get him to talk about what had happened but he'd numbly told her that the phosphate readings that had sparked his curiosity had been a false positive and that he was pretty sure rouge sulfates had caused the interference. Then he'd walked off, claiming to have important things to do.

Now, it was the one most important thing in her entire universe.

Three hundred and forty one hours, sixteen minutes. The Doctor forced his eyes off the clock and onto the equipment he was supposed to be operating. He'd overshot the required wavelength by several nanometers, again. In other words, he thought to himself, you've buggered up something a high school student could do stoned.

How was it that time seemed to have died? Because that's what it felt like to him; like time itself was dead. Two weeks that stretched into his past forever because he couldn't help himself, he just kept going over what he'd done wrong and how much it was going to cost both of them.

He'd lose her, soon probably, as she grew too uncomfortable with him around and asked to be taken home. And because he'd been selfish, had thought himself so impressive he couldn't be wrong, he'd misread the signs and overshot the relationship. She was going to miss out of seeing the universe because of him.

Looking back down to the AES, he realized that not only had it finished running the sample but that the internal flame was a good two hundred degrees too high to be useful for anything. He hit the switch and pushed his chair back, letting it roll to a stop in front of a clear area on the bench. Leaning forward he crossed his arms on the table and buried his head in them. The smell of ethanol and hydrochloric acid assaulted his nose and he pulled back, the faint sting still on the nostrils.

"Hi."

He swung around to find Rose leaning on the doorframe of the lab door. He swallowed, taking her in, even though he told himself she wasn't his to take in. From the slightly messy hair and the fact she had no shoes on he guessed she'd just got out of bed. Jeans and a T-shirt and she still looked a goddess.

You don't appreciate what you've got until it's gone. Who ever had come up with that was wrong, thought the Doctor. He'd appreciated her, had thought her a goddess from day one with intelligence and humor and goodness to match. It just hurt more now. But he'd always appreciated her.

"Hi," she repeated again, resting a hand on her hip and forcing a smile.

"Hi," he replied, unsure what she was doing, unsure how he'd handle it.

"I've got a chemistry question." Rose did her best to sound playful instead of scared, though the distant look on the Doctor's face indicated that he wouldn't notice the difference.

"Oh, yeah?" He turned and picked up a beaker and a pipette, the two things nearest him. The pipette was contaminated and the beaker was full of lukewarm black tea, but she didn't have to know that. Accommodating, answering to her every need, but he couldn't bear to look at her.

"Yeah." Rose had her foot in the doorway, figuratively if not quite literally. "You said that you got a false positive on the phosphates?"

He nodded, using the pipette to transfer three milliliters of tea into an empty conical flask.

"Can you get false negatives?" There was the bait, he'd take it, she was sure.

"Nope."

Her face fell but he didn't see it. He'd had two choices, tell her that yes there were false negatives, that they occurred rarely, much more rarely than false positives. They were difficult to account for since, while it's easy to contaminate a sample and get a false positive, to accidentally remove a particular component from a mixture is very hard. That he'd only ever encountered false negatives twice, on both occasions dealing with complicated, volatile samples. No, too much chemistry, too many words. So he lied and hoped she'd leave before he hurt her again.

She didn't, instead he sensed her hovering in the doorway for several seconds and then felt the air grow thick as she walked in, stopping a few feet away. "What?" she asked.

What what? What the hell was going on? Why did she care about false negatives? Why was she screwing with him? Why was she back in his lab when last time she'd given him the wrong signals and gotten herself hurt. He hated himself for blaming her. He was the scientist, his observations were wrong. It was his fault. But he was angry.

He retraced the snatches of conversation that had interwoven with his thoughts. "Nope," he said, trying to keep his voice light and conversational, "False negatives don't exist."

"Yes they do," she fired back and he resisted the temptation to look, to see her.

He could continue the falsity, hope she'd believe him and trust him because he was the expert, or he could admit he'd lied and try to explain to her why he'd felt it best that he limit their conversation. He looked at her, eyes as dull and dead as he could make them because that was better than letting her see he was angry and passionate and in love with her. "No such thing as false negatives."

There was one way to get through to him. It was chemistry, she was sure, and she'd found the double entendre, even if it didn't make complete sense to her, it would make sense to him. But he was lying to her. Regardless of how slack he forced his face, how blank his eyes went, she already knew there was something underneath and she was going to push this.

"False negatives do exist, I've read about them." He looked ready to assure her that she was reading the wrong book. "In your chemistry books, from the library."

He shut his mouth, he couldn't challenge a chemistry book; she'd caught him in a lie about chemistry. The irony did not escape his notice. "Why are you reading chemistry texts?" It was the logical, objective question. Science was objective. He was a scientist, he'd be objective.

"It doesn't matter," she rushed. She moved close, sliding onto the bench top a little to the right in front of him, noting his startled, confused look. She calmed herself enough to say, clearly and convincingly, "I gave you a false negative."

He didn't understand; she was speaking his language for the first time and he didn't understand. "What kind of false negative."

"No one can ever really explain where false negatives come from, they're just freak occurrences and they happen at the most terrible of times, yeah?" He wasn't reacting, but that was a good thing, she was explaining what had happened but in terms that he didn't connect with emotion and he was unable to react.

"Yeah."

"When I told you to stop, that I didn't," she paused, still unsure of what exactly she had meant. "It was a false negative. I didn't want you to stop. I don't know why I even said it."

He stared at her, managing, thankfully, to keep his face expressionless as it all crashed over him. She'd used chemistry to get him into this position, to give her control over the admissions and the conversation and the emotions in him. The internal debate that was suddenly a thousand times stronger set in motion a chain reaction; the chemistry falling into place and the fortnight's pain and frustration and fear coursed through him as adrenaline, turning into anger. Anger at himself, anger at chemistry, at their chemistry and anger at Rose.

He vented, speaking more words to her in twenty seconds than he had collectively in two weeks, "I know why you made me stop. A million reasons; you're not over the regeneration, you like the old me better, I'm an alien, I'm nine hundred years old, or maybe, just maybe, you're not attracted to me. That's fine, pick any or all of the above, that's what prompted it, stick to it. As for your 'false negatives', whether that little antic is a result of you wanting to be nice or because you think I'm going to kick you off the ship because you wouldn't kiss me, doesn't matter. You owe me nothing, Rose Tyler, least of all excuses."

Objective, that was the point of being a scientist. To be able to analyze and calculate, to find the truth. Realizing he had nothing else to say, he turned back to the work in front of him. He found a beaker of tea and three conical flasks with precisely pippetted three milliliter samples. He clenched his jaw, swallowing the anger and the frustration, and looked for some real work to do because fooling Rose wouldn't cut it anymore, he had to fool himself as well. He missed the resolute look that appeared on Rose's face.

She reached out and, unable to decide whether slapping him or caressing his face was what he deserved, she settled for cupping his cheek and turning his face towards her. "I love you."

Screw it.

There was one thing in the entire universe that was going to be able to make him lose control and he didn't know it existed. Not until it happened.

He was out of his chair in seconds, startling her with his movement and the sudden life in his eyes. Grasping her hip with one hand, the other winding into her hair, he pulled her to him, crushing her lips with his.

Shocked for only a moment, Rose lost all hold over rational thought and just went with what felt right. He was kissing her and it felt perfect, his hands rough and insistent, passionate just like his eyes had been in the instant it took him to react. Opening her mouth to his forceful tongue she couldn't help but moan, the sound catching in his mouth and the tiniest smiled detectable on his lips.

Moving her hands up his chest so she could wrap her arms around his neck, she unconsciously edged forward on the bench until she was so close to the edge she would have fallen off had he not been so close, pressed against her from head to toe. She broke away for a second, taking a huge gulp of air, hating herself for needing it. In that single second's break, his mouth swept across her jaw and down her neck, stopping to scrape his teeth over the pulse point.

Rose moaned again, her hands finding their way into his soft brown hair, urging his lips back up to hers for a second dueling kiss. In those few second he tried to focus every sense on her. He'd closed his eyes and he couldn't see and even if noise still existed, the ringing in his ears would have been blocking it out. But smell, taste and touch were compensating.

She smelt like rain, hard, pelting rain, the kind you try to escape while knowing you can't. She tasted like it too, like fresh water with a hint of something sweet, not to mention the clichéd but true subtlety that was fundamentally Rose. And the way she felt, he edged his fingers under her shirt and along the curve of her back; she felt soft and warm. When she moaned, he felt it reverberate from her skin into his, her lips into his.

None of this actually registered in the Doctor's mind, but he knew it, knew the essence of it, but actual words weren't playing an important part in his cognition. He pulled back, forcing himself not to take this too far and surprisingly content just to bask in having finally kissed her. He breathed heavily as their foreheads rested together and he couldn't help but grin at her labored breathing.

Rose concentrated, she had to be prepared for wherever he took this next, knew the fight wasn't necessarily over. But she could feel his breath on her face and her neck, knew she was breathing in what he was breathing out. Exhaled breath had three main components, carbon dioxide, water vapor and heat. Basic biochemistry, she recalled. She really was breathing him in.

While Rose was thinking about chemistry, the Doctor kept his eyes shut, the closest thing to rational thought was the overwhelming compulsion to say something that summed it up. Some strange part of his brain kept insisting that 'Bah' covered the situation pretty well, while another was relatively sure 'Guh' was a better option. That was the extent of his intelligence.

Rose smiled, taking careful note of the tight grip the Doctor had on her hips, the hand that had been in her hair descending as she leaned back until her head touched the wall. She watched him as his eyes snapped open, brown eyes practically swimming with passion. And then confusion. She felt his grip beginning to loosen and quickly placed her hands on top of his.

"I mean it," she whispered, unable to find enough strength to say it louder but hoping the conviction of a husky voice was worth something.

"That you love me?" he asked, eyes narrowed as he slipped back into objective researcher. She'd convinced him, to a certain extent, not that he would have been able to methodically write how she'd done it, but she'd made her point.

"Yeah," she grinned, liking the feeling of having admitted it. Absentmindedly, one his fingers started to draw unimportant patterns across her back.

"So why did you tell me to stop two weeks ago?" He sounded serious, though his fingers were making sure Rose knew he was well on the way to believing her. This was about closure, curiosity perhaps.

"I dunno." Bringing one hand away from his at her hip, she threaded her fingers through his hair, playing with it as she watched for his reaction. She really did have no reason for her actions but his expression wasn't sure. Always the scientist, he'd always think there was a cause for everything. "Could it have been a chemical imbalance in my brain caused by months of wanting desperately to jump you?"

The shocked look that passed over his face made her smile all the more. "I like you in a lab coat, by the way," she said, pressing for another startled look.

He just grinned. "I know."

Her turn to look a little taken aback. She reverted to seriousness, sensing the smallest bit of doubt in his expression. "We okay then?"

"Yeah," he paused, look down at to where his hands still rested on her hips. "I'm sorry."

"For what?" she almost spluttered.

"I overreacted, when you told me to stop, it just felt...It felt dreadful, I just, I didn't know what to do, so I," he paused, still not looking at her. "I just overreacted. I'm sorry."

"You are such an idiot."

"Why?" He sounded like a wronged little boy and she ruffled his hair, the silky strands ending up messier than they'd begun.

"It wasn't your fault." Pausing, Rose realized that they might never know what had caused the false negative. "Doesn't matter now."

"Indeed." They fell into comfortable silence, her hand sliding around to play with one of the buttons of his cotton shirt and his fingers continuing their meandering dance against her skin. "Hey," he spoke suddenly, looking up to catch her eyes with his. "I love you too." And he ginned his manic grin at her, eyes alight with a million different things.

Sliding her hand down his chest, over his abdomen, she slipped a finger into a belt loop and pulled him in closer. Kissing him once, twice on the mouth, she let him take control. His hands found hers a moment later, fingers entwining as he kissed her slowly, tasting her properly and actually committing the sensation to memory.

He pulled his lips from hers, noting the slight pout at the loss. He smiled before nuzzling the T-shirt aside and kissing her shoulder, her collarbone and the hollow of her neck. Each time, he paused, smelling and tasting, taking note of the difference in temperature, texture and, most importantly, her response.

"I'm rather glad you introduced me to chemistry." She whispered it into his ear, purposely making her voice lower and huskier than it really was, trying to elicit a response.

She did it just as he was scraping his teeth over the curve of her neck, the cheekiness of it tempting him into biting down with just the right amount of pressure, a low hiss escaping her lips his reward.

Damn him, she caught his lips with her own, devouring him until they once again had to break for oxygen. "It's ironic really," she said, baiting the line because she was sick of him beating her at the chemistry.

Waiting for her to continue, he lifted one of her hands sill grasped in his and kissed the back of it. "What's ironic?" he asked, realizing he was expected to ask. He kissed each of her fingers and then the underside of her wrist."

"The catalyst." He paused, she was not going to do this to him. "For this reaction. You and me. It's ironic that the catalyst was chemistry itself. You know," she could hardly keep from laughing. "Usually its porous, or a metal maybe. But for us, it was the entire field of chemistry." She stuck her tongue between her teeth, watching as he looked up at her, jaw clenched to keep himself under control. "If you'd never told me how subtle it was, the way the particles fit just right, the sweetness, the forcefulness, we never would have gotten here."

He released a breath slowly. She knew perfectly well that her talking about chemistry with that look on her face and that tone to her voice was quite capable of making him react in ways rather primal. Leaning forward, he gave in just a little, settling for a slow passionate kiss that left her breathless enough to give him time to respond.

"You're wrong," he told her, watching as her expression fell. "Catalysts, by definition, only speed up a reaction. We still would've happened." He ginned at her, adoring her that little bit more for the way she tilted her head and ginned back. "The chemistry was undeniable. We're a million little subtleties that just had to explode. It just would have taken longer."

"Better this way though," she pointed out.

"Oh yeah." He nodded, leaning forward, finding her irresistible.

She avoided his lips long enough to ask, "Now what?"

Letting slip a sly smile, he paused, mouth but a tantalizing inch from hers, "Experiment a little?"

That's it. No more. Oh well…would love to know what you guys thought of my whole take on 10…this is my prompting for reviews…Oh and I just remembered, the reason this one took longer than the rest is because I had my mid semester Chemistry test on Thursday. I am very confident that I absolutely kicked its butt. There was even a question on phosphorescence which made me smile.