Optimism isn't hard, if he logics himself into it. He's alive, he's healing, they can save what's left of his team, and one of them will surely be able to zip him off to Oslo, where Michael and Walter are. It can still be okay.
"Peter was mistaken about me. I won't let the others suffer."
(no subject)
"Peter was mistaken about me. I won't let the others suffer."