It's her eyes that kill him, that knock him backwards. Sometimes, he finds himself gasping for breath, because just looking at her is like an unfair sucker punch. He never sees it coming, no matter how hard he tries to prepare himself. mark/lexie -- somewhere in season five, between episodes thirteen and seventeen. one-shot.

I'm on a Mark/Lexie kick. I can't seem to stop. This is mostly about Mark's point of view and thoughts on his developing relationship with Lexie in Season 5.

He stirs as he hears the door open, a small smile creeping across his face before he can instruct himself to play it cool. Of course she notices. She's the type of girl who notices everything vulnerable about him, much as he might hate that about her. The strangest truth is how much he's not bothered by her openness, the complete ease with which she tiptoes over to him, grinning broadly, as if this is a familiar routine. Granted, they'd been sleeping together for a few weeks now, but she just never seems nervous around him. It's making him nervous.

"Do you want to go home?" she asks quietly, climbing into bed with him. He eyes the door to the on-call room, grateful that she's remembered to lock it.

She doesn't specify as to where home is, which strikes him as funny. He has half the mind to taunt her about this, but resists, knowing that he doesn't really care where he sleeps tonight, so long as she's next to him. She's changing him and he's not sure how he's missed this pivotal transformation, but he did and he's so much different now. Better, even. Maybe.

He pulls her closer to him, wrapping one leg across hers protectively. "Let's just stay here," he says tiredly, burrowing his head in her neck.

He can't see her, but he swears to god he can feel her grin. It's all of these subtle observations that he's beginning to just inherently detect about her that terrify him. She's little Lexie Grey and whatever this is can not last. They both know that. She's off-limits.

She turns towards him and he rolls onto his back as she stretches out across his chest. "You don't feel like sneaking into Meredith's attic again?" she replies, teasing him, her hand stroking his abs lightly.

Mark chuckles. "No, I just don't want you calling me Anne Frank again," he grins, running his fingers through her hair gingerly. She's become like a drug for him and he's not sure he's going to be able to quit her. They can't keep going on like this for much longer, that much is apparent. He's just not sure what else he can do.

He feels her smile into his chest. "Here's good," she says, still stroking his stomach rhythmically. "I kind of like it here."

"Me too," he agrees, fingers massaging her head softly. He listens to the rise and fall of her breathing as she begins to relax, her eyes closing slowly. "Tell me something," he all but begs. The unrecognizable softness in his voice surprises even him. Were it anyone but Lexie Grey laying on top of him, he'd be disgusted with himself. He barely recognizes who he's become, and to make it worse, he doesn't really mind.

"What do you want to know?" she asks sweetly, tilting her head upwards towards him.

He can't take the sight of her sometimes. She's too stunning, lying there looking up at him, exhausted and weary after a twenty hour shift, and all he can think is that he can't fucking remember her ever looking this fucking gorgeous.

"Anything," he manages raspily, adjusting his body as she falls into the nook between his chest and arm. He brushes her hair back from her face, locking eyes with her. It's her eyes that kill him, that knock him backwards. Sometimes, he finds himself gasping for breath, because just looking at her is like an unfair sucker punch. He never sees it coming, no matter how hard he tries to prepare himself.

She surveys his face carefully, as if weighing him, deciding whether or not she can fully trust him before she lets her lips fall open. "I found out about Meredith when I was thirteen," she starts, eyes still scanning his face. "I found some pictures and letters in my dad's study."

Mark strokes her cheek lightly, watching in amazement as her face softens under his touch. He loves to hear her talk, to hear her say just about anything. Just the sound of her and the extreme emotional highs and lows in her voice keep him captivated.

He squeezes her shoulder lightly. "Did you tell him?"

She shakes her head. "No. I didn't–I thought—I thought that if I brought it up, he might–he might....." she trails off, eyes skirting away from his, gaze falling downward. "I didn't want to meet her, to know her. I didn't want her to exist. You don't like to find out that the people you thought were infallible are capable of terrible things. I mean, I idolized him."

"Does Meredith...."

"No," she says quietly. "I doubt she'd care. She'd probably just hate me more if anything."

"She doesn't hate you," he insists softly.

"Well, she doesn't like me," she adds, meeting his gaze head on.

He can hear the disappointment in her voice, the hurt. There's nothing he can do to change her relationship with her sister; he can't make her life here easier. Instead, he kisses her lightly. "I like you," he says before he can mull the words over in his head. If she's surprised to hear him say that, she doesn't let on. That's another thing he can't quite wrap his head around. When he does something completely out of character, she just glazes over it, like she knew it had been coming. He can't decide whether he loves or hates this about her.

"You're not bad," she informs him, arching her neck to greet his lips with hers. He kisses her back hungrily, lost in her for a moment before the full weight of her words registers with him.

This is Lexie Grey. Lexie frickin Grey. He's already betrayed Derek enough for one lifetime.

"I am," he insists, dangling the words in front of her like a warning.

She sighs lightly, eyes peering back at his brazenly, daringly.

"I'm not afraid of you," she tells him decidedly, before kissing him again. Her lips meld with his as he flets his hand roam under her shirt and up her back, his heart pounding frantically in his chest.

Little Lexie Grey, what have you done to me, he thinks helplessly.