Spoilers: Through episode 2.16, "Olivia. In the Lab. With the Revolver.".
Disclaimer: I don't own Fringe or its characters.
A Waiting Game
Olivia is skittish.
Things between them are awkward, more so than back in the beginning when all Peter knew about her was that she bluffed like a pro and had a penchant for taking stupid risks for the people she cared about. Ever since that near kiss, she's avoided his eyes and barely let herself relax, burying herself in work and solitude and sleepless nights.
Whatever this attraction is, it's out in the open, the unspoken elephant that's taken up residence between them. For him, it's been there for months; fully acknowledged if only to himself from the moment he watched her pale and lifeless in the hospital bed and realized the depth of his mourning. He bets the first time she let herself think about the possibility, though, was that night when she leaned towards him with her defenses down.
And he responded without thinking through the risks.
There, at that moment, she was just as willing to take that step as he; he'd moved slow enough to make damned sure of it. It wasn't until later, once the giddy triumph of the night wore off, that she started to think about her actions and the possible repercussions. If he ever needs a reminder that he pushed too hard, too fast, all he has to do is catch one of the quick, sidelong glances she keeps giving him, the wary glances of a wild creature sizing up a potential threat with equal parts interest and trepidation. She's off balance and withdrawing while she tries to regain her equilibrium, and if he's not careful he could fuck this up and scare her away.
He knows Olivia well enough—or thinks he does, anyway—to realize that if she really wasn't interested, she'd have made it clear by now. Besides, nothing about those looks of hers say "not interested", just "not ready". He can give her the space she needs to figure out what she wants to do.
He wants—needs, maybe—to keep her as a friend; that's a priority. Top of the list. Anything else? He'll watch. He'll wait. And maybe, if the time comes when she's ready, he'll get a second chance at making his move.