[ He pretends he doesn't notice, because that's Peter in many forms: seemingly bored, indifferent, always off doing his own thing which may or may not have shady relevance to the most recent bullshit, always an outsider, never a friend or a father or the least bit reliable, even if he is right here, quite close, highly attune to Chris' reactions.

Then there's the other recurring motif of his behavior, which is boundary testing. Chris doesn't pull away, though it was a near thing. Chris thanks him, though he means what are you doing and why. Being given an inch, he'll be on the lookout for a handy mile from now on. Not now, of course. For now he just lets his hand slide limply off the shoulder like it's worn out cat, flexes it idly to make the black veins go away faster as he brushes past Chris to peer out the door and up the stairs. He's done here, but isn't sure if Chris will insist on dealing with the bodies. ]

Don't want to be young again, huh? Wouldn't that be inconvenient. You'd go right back to trying to kill me. I'd have to be really nice to you.

[ No denial that he's enjoying this. He is, for all the reasons Chris considered, and more, and he is audibly smiling because they probably won't be addressing why Peter is being so nice to him right now, probably for the same reason Chris didn't pull his arm away in the first place. ]

So are you gonna make me carry a bunch of bodies now, or can we just. Close the door and go? Decomposition sounds like a problem for future me.