"You belong with me."
Maybe it's a little corny. Maybe it's ill-timed and they're probably going to be fugitives soon and maybe even dead. Maybe, someday, it won't be enough, but for now those words on Olivia's lips and the soft brush of her mouth on his - those are what he needs.
He kisses her back. There are a million things he wants to say, but for right now all he has the strength to do is press his hand to the small of her back. The relief rushes out of him so quickly it aches, and for the last few seconds of the kiss he wraps both arms around her and hopes she understands that it's not Walter he's coming home for, it's not the FBI or anyone's damned quest to save the world - it's her.
"Best you can do, Agent Dunham? I must say, I never knew you could be so...cheesy."
She swats him on the shoulder and smiles, and it's that smile he's been swearing he'd tease from her since the beginning, it's Olivia the woman, not Olivia the cop, or even Olivia his friend. It's his Olivia.
"We've gotta get out of here," she says, and starts pulling on his hand towards the door. "We've got about three hours until we don't get out of here at all."
They start to leave but before they go, he stops her.
"Olivia -"
She turns back to him, and he almost doesn't feel it when she squeezes his shoulder.
"I know, Peter. Let's go home."