Spoilers: Just Jack, I reckon, and the fact it's set straight after "Boom Town".

They were on their way to Raxacoricofallapatorious, following the near-fatal encounter with Margaret Blaine, the disguised Slitheen, on earth. Jack had retired for a bit of beauty sleep - and to dream about the extrapolator he had now claimed as his own - which left Rose and the Doctor alone in the TARDIS's control room.

Rose was sat on the chair opposite the control panels, idly knocking her knuckles against the bars behind her, whilst the Doctor was again stood up on his little scaffold in the rafters, keeping up an appearance of fixing something (though Rose knew he was just fiddling because he could never keep still; just sitting down and relaxing would be far too 'domestic' a thing for him to do). Despite the outward serenity of this scene, though, there was in fact a most tangible tension in the air. If one was to wander into the realms of metaphor, then one might say there was a taut piece of invisible wire stretched between Rose and the Doctor, and the longer the two went without saying anything to one another, the more taut and strained this wire became; and so overwhelming was this, that it soon got too much for Rose's liking, and she began to feel incredibly uncomfortable in being there; it was almost as if she wasn't wanted there, and yet she had no inclination of moving, or of even trying to initiate any sort of conversation with the Doctor. She was far too stubborn to give in to anything like that.

Fortunately, the Doctor, at least wasn't thinking along the same lines. "So," he said at last, glancing down at her and at once dispelling the tension, like a needle bursting a balloon, "What happened?"

Rose stared long and hard at him, her mouth slightly agape. "Huh?" she asked, slouching back in her seat so she could look at him without cricking her neck.

"Mickey," he explained, his eyes returning to his task and his fingers playing about with several loose wires. "What happened?"

Rose sighed and turned her eyes down. She felt like running from this discussion, for some reason; it was going into the 'no man's land' of her and the Doctor's conversational territory, a place they had never before taken their words, and which she had thought they had silently agreed never to do so. "Nothing…" she thus mumbled. "Nothing happened."

The Doctor made one of his unconvinced nods. "Oh yes… which is why you walked through the door in tears."

"You didn't say ought at the time."

"Had you wanted me to?"

She found her gaze suddenly locked with his again, and she realised, with irritation, that he was justified in this response - he more likely than not would have had his head taken off if he had asked why she was crying earlier on. This didn't mean that she liked the fact he hadn't, though, so she decided not to reply in the end, and she just settled with another sigh, listening to the small, tinkering sounds the Doctor made as he continued to work overhead.

After another few minutes, however, he brought the topic up again; "Did you fall out?" he asked.

Rose felt the anger flare up within her, the previous tension of the moment and his words combining to grate heavily on her nerves. "Yeah, because you'd like that, wouldn't you?" she snapped.

He stared down at her with a look of mild offence on his countenance. "Sorry I asked," he said.

Rose ran her hand through her hair and sighed another time. "Sorry," she apologised half-heartedly. "I just feel so bad…"

"About what?"

"It's so difficult," she went on. "To think that in here, we're in our own little world, going along on our own little timeline, whilst, out there, back home, mum and Mickey and everyone are living a normal life in real time, and…" She closed her mouth, confusing herself. "It just seems so terrible that I'm out here and he's back there and --" She lost the plot and gave in. "I don't know."

She nearly jumped as the Doctor suddenly landed before her, having leapt off his platform. He smiled broadly. "All done," he said, and began to pack his tools away.

Rose sighed, his apparent indifference serving to wind her up a bit. "And you don't care, do you? You just come and go however you please. It doesn't mean anything to you that my mum and my mates are back on earth, living their lives, whilst I'm trapped in this limbo."

"You're a bundle of laughs, as ever," he muttered, his tools clattering and clanging as he piled them up in a small box.

"It's just so… difficult."

He threw his last spanner into the box then turned to look at her. "No one's making you stay, you know," he said.

"I know," she rallied, "I want to stay, but--"

"Then what's the problem?"

She wafted her hands about for a moment, vainly seeking for the words she needed - but she couldn't find them. The Doctor wasn't human. He didn't think like her, at least not most of the time. "Forget it," she said at last. "I'll never get through to you."

She expected him to grin and carry on, but he didn't. His face remained solemn and grave, and his intense blue eyes didn't leave hers.

"What?" she asked.

The shadow past and his face brightened again. "Nothing," he said, before he wheeled about, trotted round the other side of the TARDIS, and was lost from her sight behind its central column.

"You don't communicate well, do you?" she continued.

"Nope," he piped up in return.

She smiled faintly at this before she stared up at the great, rounded ceiling of the TARDIS. "What were you doing up there, anyway?" she enquired.

"Like you'd understand."

"Tell me."

He peered round at her. "Nothing," he said.

She leant her head to the side to get a better look at him. "No, really, just tell me," she insisted.

"I just did."

Rose stared at him for a while until it clicked and she smiled. "You idiot," she chuckled.

He threw her another of his grins in return, before his head again disappeared behind the column.

"Why were you 'doing nothing', then?"

She heard him sigh before he paced around the controls and came back into view. "Because I wanted to," he said plainly.

Rose found her smile lengthening into a smirk and she slid onto her feet, taking a couple of steady, sauntering steps toward him. "You must have a reason," she said.

The Doctor was smiling at her again, but in a more gentle way. He did, however, look a little on-edge, as if he was becoming uncomfortable with where this was leading. "No, no reason," he went, doing his utmost to keep his demeanour flippant.

Rose closed the gap and toyed with the collar of his jacket. "Do you know what I think?"

He just stared at her.

"I think you want a bit of 'us' time again."

He continued to stare.

"Just me and you, like it was before. Before there was Jack, and before there was Adam--"

"Oh, leave him out of it…" the Doctor groaned.

Rose laughed. "Poor lad. You just kicked him out there, with that head-opening device in his…er…"

"Head."

"Yeah… in his head." She shook her head. "You were so cruel."

He smirked at her. "Oh, but I wasn't the only one teasing him, was I, Rose?"

She feigned innocence. "I would never."

"You would and you did."

She laughed again, looking down as she now fiddled with the buttons on his jacket. "I know…" she conceded. "That was really bad of me."

She watched as the Doctor's hands slid over hers and he pried them away from his jacket. "Stop that," he said.

He didn't say it harshly or ought, but it made Rose feel incredibly putout. "Why?" she challenged him.

He continued to give her that kind but sad look. "Just do."

She made a point by tangling a couple of her fingers into the button holes and anchoring herself to him. "Oops…" she sighed, staring him directly in the face so that she could gauge his reaction. "I seem to be stuck here."

His expression didn't budge.

"Well, you got what you wanted," she went on, aiming for the provocative approach. "Mickey's going out with Tricia from the shop…" And she then unintentionally slipped back into her own world; "Tricia Delaney… he doesn't even like her. He's just doing it to get back at me."

Now the Doctor smirked.

"I can't believe he's done that… just out of spite!" She tugged on the button holes of the Doctor's jacket. "Bloody Tricia… she's nothing to look at, you know?"

The Doctor was giving her an irritating smile now.

"What?" she asked.

"Rose Tyler," he said, shaking his head.

She felt herself smirk again - he was teasing her now, wasn't he? "Stop that," she said, giving his jacket another harsh tug. "It's true. She's not his type."

The Doctor nodded. "I see… and you are therefore jealous because…?"

"Jealous?" she spat in disbelief, scoffing at him. "Why would I be jealous of her?"

The Doctor's eyebrows rose. "Hmm… I wonder. You have funny little brains, you humans. There's so much emotion squashed up inside them, and most of it's over things that are really trivial and petty."

She pulled her fingers from his buttonholes and slapped him light-heartedly on the chest. "Oi, you can be just as 'petty', mister high-and-mighty life-form."

His consequent smile told her that he had no doubt.

Rose heaved a great sigh at length and instinctively leant toward him, until her head touched his breast, and she settled there, her mind buzzing with hundreds of different thoughts, all of them loose ends, waving about and looking for resolutions. She didn't look to see whether the Doctor was surprised or not by her sudden act of trust and affection - she was too busy thinking about everything. "Bloody Tricia," she mumbled on. "It won't last."

"And you and Ricky did?"

She leant back so that she could look the Doctor in the eyes. Her first instinct was to have a go at him, but as she stared into those two blue orbs of his, she felt her words arrest in her throat; her and Mickey weren't an item anymore, were they? She had made sure of that the moment she had crossed the threshold of the TARDIS and left him, alone and bewildered, on planet earth, 2005. Poor Mickey.

"I guess not…" she murmured, resettling on his chest. "It's just all so difficult."

She felt one of the Doctor's hands come to rest hesitantly on her back before he rubbed it up and down. "This isn't a bad life," he said.

"I know that… but I've had to sacrifice so much."

"But you can always go back home. It'll always be there for you. But not for me… I can never go home."

A tremor of fear ran through Rose's body at that, a fear, not for her, but for the Doctor, a fear for his safety and his life. It seemed so stupid now, to think that he truly had nothing, and here she was whining about Tricia bloody Delaney. Things suddenly seemed worth sacrificing if it meant giving this man some hope and respite, both things which he deserved so badly. He gave so much for everyone else, after all, and most of the time no one even realised he'd been there, saving their world.

She tightened her arms about his waist and held him tight. "You've got us," she said. "Me and Jack. We won't leave you."

Rose felt a slight tremor in his chest then, a noise which might have been a scoff or a contented sigh, but she didn't dwell on the thought - she just pressed her head closer to his chest and listened to the pounding of his heart; puzzlingly, it seemed to echo…

She pulled her head away and gave him a frown, one which made him raise his brow in turn. "What is that?" she asked, placing her hand flat against his chest.

"My hearts," he said.

"Hearts?" she gasped, beginning to move her hand back and forth over his breast as she sought out his second heart. "You have two?"

"I'm not human," he reminded her.

Admittedly, she had quite forgotten that he was alien - at least in body, because he appeared so human - and she just smiled to herself, quite amazed by this discovery. "That is so weird," she said.

Her naivety heartened the Doctor a little and he just chuckled at her.

"It is, though," she went on. "I mean, why do you need two?"

"In case the other one fails."

They both laughed and Rose leant back against him again, listening intently for his dual heartbeats. "No, seriously."

He shrugged. "Evolutionary whim. Why do you have two kidneys?"

"You don't have two?"

He wouldn't answer that one. He just gave her a teasing smirk, which brought out the cheeky grin on her countenance; "What else don't you have?" she asked.

"You come right out of that gutter, Rose Tyler."

"That's Captain Jack rubbing off on me."

"Well, we'd better stop his 'rubbing off' on you. You know who'll get the blame when we next see your mother."

"Oh, my mum won't be surprised by anything like that. I'm not a kid, you know?"

He smiled at her another time before he pried himself away and busied himself back at the TARDIS consoles again.

Rose watched him for a moment before she followed him, stood by his side, and said bluntly, "I like you."

He paused and gave her a miffed look. "You like me?" he asked, as though it were a bizarre thing to say.

She nodded. "Yeah."

He smirked again. "Well, after all our little adventures together, I'm glad to have finally found that you 'like' me."

"I didn't mean it like that."

"Then what did you mean?"

She became a little more serious. "I don't know…" she mumbled, her smile fading as she turned away and realised the possible consequences of this conversation. "Things are just…"

She jumped as she felt the Doctor's hand slide onto hers. "Difficult?" he asked.

They stared long and hard at one another until Rose felt herself drawn to him, as though her head were magnetically attracted to his, and she suddenly had the desire to kiss him, just once to see what it would be like; that would be something, though, wouldn't it? To be able to say you'd kissed an alien. Not that he seemed alien… he just appeared so human right now, so… perfect.

She leant up toward him, her heart pounding, and saw him dipping his head in turn, his breath fluttering over her face, and--

"Hey, there's some strange noises coming from those trash cans… You might wanna check 'em out, Doc'."

Rose exhaled, closing her eyes in frustration, whilst the Doctor snapped away from her so rapidly he may as well have been electrically shocked, a fact which only served to make Rose feel doubly worse. They both then avoided one another's eyes as they turned to watch Jack waltz into the control room, dressed in the most tasteless dressing robe known to mankind.

The Captain, however, was not to be so easily had, and he shuddered to a halt as he felt the sudden change in atmosphere, glancing between the shifty-looking pair with a knowing grin. "Oh, gee, I'm sorry, guys," he grinned, "was I interrupting something?"

"No, nothing," the Doctor countered in his typically jovial way, quickly burying his feelings back down in the depths of his chest and refocusing onto the task at hand.

Jack smiled again, revealing his perfect row of white teeth. "Aww, come on… that looked like a moment."

Rose felt herself blush a little, feeling rather stupid now. "Yeah, a real Kodak moment…"

"Ko-what?" Jack asked.

She wafted a hand at him. "Nothing."

The Captain shrugged. "Well, there's always room for two in my bed, guys. Three might be a squeeze, but I'm up for the challenge if you are." He winked at them before he again left the room.

The Doctor exchanged a glance with Rose and she smiled back at him. "He's just kidding around," she said.

The Doctor looked more than a little ashamed, as if he'd just done something terrible, and he glumly nodded in return. "I know," he said, before he hung his head for a moment in silence.

Rose felt terrible herself now, and was unable to comprehend why the Doctor had reverted to such a state of mind. She was about to raise a hand to his arm, to offer him some comfort, when he suddenly turned on her, gave her a quick smile, and then simply left the room, brushing his hand lightly along her arm as he went.

Rose breathed shakily, freezing to the spot and involuntarily running her fingers over her skin where he'd touched her until she heard his footsteps die away. She then just heaved a great sigh, slumped against the consoles, and gazed pensively into space.