He's also not good at making friends, which is why he can't figure out why Derek ever hung around. Sure, they were a lot alike for a while, and they vied for the same girls and they fucked the same girls and they were the best in their class and the best at what they did and they were going to rule the world.

Until Addison.

But even then Addison was like a third musketeer, not someone who divided them. And Mark had girlfriends and Mark had women, and Mark didn't envy Derek at all. Stood up beside him, beside them as they got married, listened to bitching and pissing and moaning and offered advice that he didn't believe in, and never once said that maybe marriage wasn't what they should have done and never once said 'I told you so' and never once said anything out of line.

Until Addison asked him to fuck her, and he said yes.

Not that it happened that way. They all hung out together with whatever girl Mark thought to bring along until the snipping and the fighting and the silences stopped because Derek stopped showing up at the bar across the street for drinks, and then Mark stopped bothering to bring someone along, so it was just him and Addison and they talked and they drank and then one night, she reached across the table and took his hand and the next thing he knew he was in Derek's bed fucking Derek's wife and it was good, it was perfect and then Derek was there.

And just like that it was over. And Mark was never sure who Derek hated more, who he was angrier with - Addison or Mark himself.

And then Seattle happened, and it's the three of them all over again, only the lines are drawn different, and he's pretty sure they both hate him now, but at least Addison still looks at him, still talks to him. She still fucks him too, but he's pretty sure that has more to do with punishing herself than punishing Derek, and he almost wishes she would stop, except then she'd stop and where the fuck would he be then?

He looks at the others - Callie and Izzie and Meredith and, hell, even Bailey - and approves or dismisses one by one. Callie's hot and he fucks her, and he uses her like she uses him, and it works for the time that it works, and then it's done. Izzie's screwed up in the head, and he's fucked enough blondes to know that it's probably not worth the grief. He watches Meredith and wonders what Derek sees, and knows what he sees, and knows that no one should combine a God complex with a knight in shining armor complex, but it works as far as he can see, but he figures that's because Meredith's got a few complexes of her own.

Bailey…well, if he didn't think she'd eviscerate him and leave him for the fucking seagulls, he'd probably do things to Bailey. He tries not to think about that, tries to keep her out of his head as much as possible because she scares him and he doesn't want to think about how much that turns him on. Plus, he really doesn't have a death wish.

And then there's this.

This. Now. This moment.

He doesn't know what to do in moments like this. Where the world is collapsing all around them. Where there are dead and dying and surgeries to do and people to care for, where there's just as much need for humanity and hope as there is for his skills as a surgeon. He doesn't have those, hasn't since whatever shred of it he thinks he had died the second he saw Derek's face in the bedroom that night, watching for that life-long second before he turned and stormed out the door, out of the house, out of New York.

But he hears the rumors, hears the clamor and fear. Nothing works faster than a hospital grapevine, and he rushes down the hall and stops at the end of it, watching Derek stare at nothing, that same look on his face, in his eyes.

Mark walks the rest of the way and stops, standing over Derek and debating his last chance to turn and run. People need him to fix their burns and cuts and vanities, and that's what he does. He fixes people, he doesn't heal them.

He sinks down next to Derek and copies his posture and reaches over, touches Derek's arm and squeezes, offering the only thing he can, the only thing he has.

It's not enough, Mark knows.

But it's a start.