He might not have picked up on the weird tension between Finn and Jess (call it blind faith), but he knows to look for her reaction after he dumped that load of information on her. Of course she'd be mad about it. He'd be furious to hear if it happened to her.

He just. Has to pretend everything is fine anyway.

He smiles at Finn with a clear, warm, fondness - but it does when he mentions here.

"Yeah. Things got real busy. And now we have to share a planet with the guy who blew up five of them."

He glances around, making sure they aren't being overheard, and leaned in. "Which - listen, Jess. I killed the guy once already. The rules are different here. Death doesn't stick here. So as much as I know you'd love to go pick a fight with them just like I would, it's not worth it. The truce is important, for multiple reasons, and the two minutes of satisfaction really wouldn't be worth breaking it."

Does he know he never mentioned the truce until now? No. Because he's an idiot.