A/N: Maddek in New York - I'll never get enough of it. Maybe it happened this way and maybe it didn't. Since the show won't give us more backstory, we'll just have to write our own.

FIVE CAB RIDES THAT COULD HAVE CROSSED THE LINE (AND ONE THAT DID)

1. Every word is nonsense but I understand and oh, Lord, I'm not ready for this sort of thing

They fall and Derek catches them, and oh how they laugh, because everything is funny on close to no sleep - even a wild taxi ride, the driver barreling down four a.m. empty streets. They're bone tired and terrified of exam results, fingers stained with highlighter, drunk on cheap two-for-one shots and end of year glee. The taxi swerves again and they slide the other way this time, Derek and Addison slamming together into Mark. Addison's smaller body hits him first, then Derek pressing them all closer. He can smell her hair, feel the soft swell of her breasts against his arm as she slumps forward, giggling.

Warm summer air wafts through the taxi. It's almost too hot, Addison's fingers curling for purchase around his knee as the cab swerves yet again. It's almost perfect.

Then she tenses under his hands, groaning.

"I think I'm going to-"

Mark hoists her up, lifting her chin. "You okay?" Derek takes hold of her then, thrusting her toward his open window for air.

The wind whips her long hair across her face and Derek bats it away, pulling her torso onto his lap.

Her legs drape over Mark's own, warm and solid and he can't resist resting his hands on her thighs in the guise of helping her balance. She's giggling and slurring her words and Derek is stroking her hair out of her eyes and smiling down at her. She drapes an arm over his neck and squeals when he buffs her with a scruffy cheek, his hands drifting everywhere.

"That's better," she mumbles.

And Mark has to turn away - if someone asked he'd say he was embarrassed for her, embarrassed for them watching the way Derek can't stop touching her. It's been a year. Not even a year. But the truth, as Derek's hand slips under her shirt and she sighs with liquor-tinged pleasure, is that he's embarrassed for himself, by the effect she has on him.

It's nothing, it's nonsense, was what he told himself, even though he hasn't been able to erase the memory of the way she looked when she answered the door of Derek's apartment, eyes sleepy and sated. "We lost track of time," she shrugged, didn't even look embarrassed to be wearing Derek's boxer shorts and one of his t-shirts, her hair a tangled cloud around her flushed face. Mark stood there, anatomy textbook under his arm, a fistful of pens. The brazen way she met his eyes went straight to his groin and then he was the embarrassed one to be sixteen years old again, unable to be near a woman without his body betraying him. And he drank her in, because he wasn't betraying anyone if he was just looking. She shifted, scratched idly at the back of her calf with the toes of the other foot and he stared nakedly at the flex and release of muscles in her legs. Unbidden rose the question of what it would be like to press his tongue to the skin just under the hem of her shorts, to trace the white column of her throat with his lips, to wrap her in his arms and never let her go.

She shifts her legs now, in jeans even though it was close to eighty degrees earlier. The seams are rough against his fingers. He steels himself, everything he has, because he can't think about this.

The problem is that he understands it now, his own longing. He doesn't put a name to it, he says no words, just stares out the window at the city lights that intermittently illuminate the face he's afraid to see. She laughs, soft and slurry, at something Derek says. He pretends it's him.

2. I am not worried - I am not overly concerned with the status of my emotions

They thought they were tired in medical school, but it's nothing next to internship. They compare the craziest places they've fallen asleep. (It's the bus shelter on Union Square South for Mark.) For Addison, it's right here on the sidewalk in front of the sliding ER doors, pale dawn light catching the circles under her eyes, leaning against an equally tired Derek while Mark hails a cab. He's been off an hour longer, showered and coffeed already.

"Whoa," Mark reaches for Addison just in time; she's genuinely asleep now and Derek, barely awake himself, sags under her weight. Mark pulls her into his arms, grabs Derek under the elbow with his free hand. "You two are a mess."

The weak sun catches the diamond on Addison's fourth finger.

"I'm awake," she's limp against his shoulder, lashes fluttering on her cheeks. "Hour fifty-four. Still awake."

He squeezes her gently, carefully. He's just supporting her, that's all. He's just helping his friend. Derek takes over hailing the cab and when one pulls up in front of them he gets in first while Mark balances Addison carefully against him. He shakes her gently awake, helps her crawl into the cab and into Derek's waiting arms. They turn toward each other like puppies in a basket, seeking out the other's warmth, both their eyes closing. Mark directs to the driver to their apartment, then slouches down against the seat. He's the only one awake. He'll keep watch.

Addison's eyes flutter open moments later, surprising him. Derek is fast asleep.

"Hey," she says quietly, scratchy-voiced. She turns her head slightly, enough for him to see her semi-stuck lashes, the whites of her eyes.

"Hey."

"I delivered three babies," she whispers. Her bare arm brushes his; it's mild mid-spring, no need for anything more than clean scrubs and the cardigan draped loosely over her shoulders.

He just breathes in appreciatively. "Three babies," he murmurs.

"Yeah."

"Why'd he go this way," she mumbles now as the glaring unwelcome lights of Times Square erupt across the cab. "The traffic..."

"It's okay." He smoothes back her hair. Across the cab Derek lets out a soft snore. "We'll get there."

Shadows dance across her sleepy smile. "Go back to sleep," he says.

Neon lights her hair. He watches her tilt her head against the cracked navy leather of the seat. Just for a minute, he pretends it's a pillow. Pretends the cab is a bed.

Pretends she's his.

3. You try to tell yourself the things you try to tell yourself to make yourself forget

She's in deep blue satin, a gold choker circling her creamy throat, and she's drunk - it's sweet drunk, not silly but not sad either. "There-" she points, a half-laugh lighting her face, but Derek shakes his head. "He's off-duty." Other people are starting to pour out of the hotel, and Mark tugs both his friends further up the block in pursuit of a taxi.

She tucks a hand into the crook of each man's elbow, typically impressive balance on sky-high heels. Mark just swallows. She's always in the middle.

They'd played the benefit true to form: Derek sitting down after one dance, Addison extending her hand to Mark. He forced himself to count, one-mississippi, two-mississippi, as he always did, so as not to seem too eager. She was only offering everything he wanted with that one hand - her right hand, no flash of gold and diamond to interfere. Dancing was permission to touch her: mold a careful hand to the small of her back, cradle their linked fingers against his chest. Her breath was sweet in his ear, a hint of her perfume lingering even after they sat down. Derek draped his tuxedo jacket over her bare shoulders as they exited the ballroom, coolly chivalrous, and for once Mark was happy it wasn't him, because he wanted to keep his own jacket that smelled faintly of her perfume. Wrapped around him, it was almost like her arms.

The only other time he gets to feel her this close is - now, Addison stumbling slightly on a crack in the sidewalk, the warmth of her falling into him as a cab screeches toward their extended arms, on-duty light blinking its welcome. Derek wrestles a half-broken door and slides in first, Mark watching with one arm propped against the roof of the cab, the other supporting Addison as she droops against him. He's always surprised at how much smaller she is under his hands than she seems at arms' length. His five fingers are all the senses, seeing, feeling, absorbing the contrast of hipbone against his pinky, muscle against his thumb, the hint of softness in the middle.

A lopsided half-smile plays on her lips. He files it away in a tight painful corner of memory with the other little expressions he knows he should stop noticing. He's never dated anyone longer than a month, but somehow he knows he would never tire of her because she would always surprise him.

Derek laughs then, reminding him of his presence. He holds his arms out to Addison but the mermaid tail of the gown won't allow her to crawl properly. Mark has to help her, circling her waist carefully, skin so warm it burns through the silky fabric. She skitters on the sidewalk in her heels and he hoists her, lifts her into Derek's arms where she looks up at him, wide eyed under the wisps that have fallen from her updo. He slouches in his seat, fiddles grumpily with what's left of the ashtray handle. Maybe one day he'll hold on. Maybe one day he won't let go.

The cab smells of cheap pine air freshener and incense and he's tired of it all: tired of handing her to Derek, tired of having to let go, tired of having to pretend.

"What's the matter?" Derek asks him as the cab turns onto 79th street.

"I'm just tired," he shrugs.

It's more or less true.

4. "Oh," she says, "You're changing" - we're always changing

He slides unwillingly into the middle seat, so unfamiliar, the hump hoisting his thighs higher than his friends'. Addison is barely looking at him, glaring at Derek who's scrolling through his emails, half an eye on the traffic outside.

Mark stares out the front windshield of the cab. He doesn't like this view. He doesn't like sitting in the middle, Derek's elbow jutting into his ribs on one side and nothing at all on his other side, Addison angled against the door as far as possible from both of them. It's cold outside, colder inside, and he works a hand into the pocket of his wool coat to retrieve his phone, to pretend to be busy.

Addison glances over at the movement of his arm.

"Sorry," he mutters as he brushes accidentally against her frosty shoulder.

"For what?" Her teeth look pearly in the half-darkness.

He's not sure what to say. For everything. But before he can form words she looks pointedly past him and says "It's not like you're the one with something to apologize for."

Right. She wasn't really talking to him; she was trying to get to Derek. It doesn't work: Derek stares resolutely out his own window and Mark sees the moment Addison realizes her husband isn't going to turn around. It registers so slightly that he's not sure if anyone else would notice - just a flicker, really. He's not even sure if he could explain it, but it's something to do with the light in her eyes, which are shining sea-green, getting just a bit dimmer.

Just a little.

And then she turns back to look out of her window and Mark sits between them, tensing all his muscles to avoid brushing against either of the back seat's occupants. No one says another word for the rest of the ride.

Each of the Shepherds slams the door on the way out of the taxi, leaving Mark alone in the middle of the closed backseat until finally he inches over and opens the door on Addison's side. He's hoping at least for a comforting whiff of her perfume but there's nothing there.

Maybe he's losing both of them.

Maybe it's better this way.

5. But she can't stop shaking - and I can't stop touching her

If he had her, he would never let her go. He shoves down the embarrassingly fierce thought as he shoves his hands into the pockets of his trench, half-turning away to give the couple some privacy. It's dusky late winter, half-frozen sidewalks and bare trees; it feels like it's raining even when it's not.

He tries not to hear them.

"But when will you be-"

"When I can. I don't know exactly when, Addison."

"Derek, can't you try to meet us-"

"No," he says shortly. "I'm sorry, Addie. I told you. Have a good time."

"Wait-" but he doesn't, just extends an arm to hail a cab, Addison stony silent next to him.

Derek opens the door when the taxi pulls up, pecks Addison's cheek, nods a thank-you to Mark, who just blinks in return, processing.

Addison slides into the cab first, stops in the middle seat as if there's someone behind the driver already.

"Addison," he murmurs as the cab pulls away.

"He said he would try to come - he didn't - he-" she chokes on the words

"Addie, I'm sorry." And he is, sorry for all of it.

"I'm fine," she whispers, pressing her fist to her mouth. He rests a tentative hand on her shoulder and she swallows a few more quiet sobs in her own fingers before turning and burying her face against him.

It's what he thought he wanted - to hold her in his arms - but not like this, not always to be left picking up the pieces. He needs to keep his distance. But then she clenches her fingers in his coat and he forgets any hesitation. He wraps her close, murmurs her name, strokes her hair, says anything he can to soothe her except that it will be okay (because he isn't sure).

"Marriage is hard work," Derek said once, in a taxi heading downtown. "Mark wouldn't have the stones for it. Right, Addie?"

"Mm-hm," she murmured, voice muffled in her scarf. She was sitting between them then, always in the middle.

Tonight she's in the center seat again but it's only Mark on the passenger side, Derek's seat conspicuously empty.

"He's not coming," she sniffles into his chest.

"I'm here," he whispers into her hair, fierce with waiting. "I'm right here." He's not going to let go.

Not like Derek did.

Because he did let her go. Just in little ways, at first. A canceled plan. A distracted answer. A dismissive glance. Mark has come to recognize her expression when it happens, curtain of hurt sliding a little further closed each time.

"It doesn't matter," she hiccups into his shirt, and he doesn't have to see her eyes to know she's lying. "I'm busy too," she excuses him as she has before - they're all busy.

A last shuddering breath tells him she's finished crying - kicking himself for knowing this too, he thumbs away the last of her tears as she pulls back. "I'm okay," she says and he nods, brushing loose hair from her damp cheeks. She settles back in her seat with a soft shaky sigh. They're only a few blocks away from the restaurant.

"Are you sure you still want to..." he prods gently and she nods vigorously, jaw set.

"Yes. It's fine."

He understands. He's still pretending too.

6. And this time when kindness falls like rain, it washes her away

He barely catches her; she's already hailing a cab on 168th Street as he jogs up, the hospital lights illuminating her bright hair. He swallows the chivalry that annoys her - he just doesn't like to see her on the street up here alone at this hour, wearing impractical shoes as usual and juggling expensive electronics.

A taxi screeches to a halt in front of them before he can comment, an old Crown Vic that's taken quite the beating over the years. She yanks viciously on the loosened door handle until he takes over, and then she slides in, folding her arms.

"Where you going?" barks the driver.

Addison ignores him and Mark glances in her direction. "Do you still want to...?"

She shakes her her head. "I just want to go home."

Mark's eyes don't leave her as he gives the driver the address of the Shepherds' brownstone, speaking loudly to be heard over the cell phone chatter emanating from the front seat. At least it gives them some semblance of privacy. Addison is stiff and silent on the other side of the seat. Derek's side. The middle hump is empty. It's drizzly dark outside, a spray of drops tapping weakly at the windows.

"Where's Derek?" he asks finally.

"He's not coming."

"Right. I thought he said-"

"He's not coming, Mark."

"Surgery?"

Her head is turned toward the window, where the half-visible moon illuminates the river; Mark studies her back. They've just left the lights of the bridge behind them and, as he so often does on late night trips home from the hospital, he'd let himself have a flash of desire to turn the cab around, drive over the bridge, leave the city behind. Take her someplace no one knows them, and -

"No," she admits, interrupting his thoughts.

"What did he say about -"

"He didn't say anything. He didn't even call. I asked the nurse's desk myself." Her tone is dully even, no emotion at all.

Oh.

Her shoulders are set. He watches her watch the city lights sweep them by. They're going fast on the West Side Highway, the glow of the buildings like sails against the water. The bridge feels miles away now, but he fights the equally strong desire to stop the cab right here, pull her out, kiss away her flat affect under the dusty glow of the street lamps. Press her up against the taxi and - one of her shoulders moves, almost imperceptibly.

"Addie..."

"It's fine."

It's not. He rests a hand carefully against her back, with the uncomfortable feeling he might burn his fingers. She sits ramrod straight but when he runs a questing finger along her jawline, light with his own fear, she drops her cheek into his palm with a sigh.

"I'm so tired," she whispers. "I'm tired of this."

"Me too," is all he can say, huskily. It's too little, or maybe it's too much, because she's turning her head now, lips brushing across his fingers. He freezes.

"Addison..."

She moves her mouth to his wrist, stops against his pulse. He's perfectly still, the shape of her lips burned against his flesh and he can feel his heart pumping, his pulse flashing against the softness of her mouth.

That same softness is against his own lips then. She kisses first, surprising him, and then she's curving into him and they fit against each other with poignant perfection: a key in a lock. A card in a slot. It's raining and it's loud against the glass, raining everywhere and fogging the windows. The cab smells like patchouli and old newsprint but then - as she covers his mouth with hers once again - only of her.

His hands are everywhere he can reach, drunk with nothing more than the heady long awaited permission to touch her. The stiff leather seat cracks and squeaks beneath them as they rock. Her skin is silk under the soft white wool of her sweater. He presses light kisses against her collarbones; she arches her back, exposing her neck and he feasts on the tender flesh there next. The heel of one of her ridiculous shoes scrapes his shins as he palms her thigh, stroking the skin he's pictured for so long. He feels the heat of her through conservative wool trousers; she gasps into his mouth and then the taxi screeches to an unwelcome halt. Mark cradles her head automatically, protectively, as the short stop pushes them both toward the plexiglass barrier. She pulls away then, running the back of her hand across her mouth but she meets his eyes directly, naked with longing and as brazen as that long-ago run-in at Derek's student apartment.

Derek...

He cups her cheek, ignoring the driver's impatient muttering from the front seat, runs his thumb gently over her kiss-swollen lower lip. "Addison, are you sure..."

"Pay the man," she says quietly. "Pay him and let's go."

"No change," Mark says, thrusting two twenties into the cash slot as they tumble out of the cab, the brownstone's formal front steps beckoning to them.

"Enjoy your night!" the driver, much more pleasant now, calls to their retreating backs.

And oh, how they do enjoy it: they exchange stiff leather for softest flannel and the wonder of finally ceasing to pretend, soaring higher and higher - until Derek catches them and they fall.

Lyrics from Anna Begins (Counting Crows).

Reviews are warmly welcomed and greatly appreciated.