He's not impressed and his look shows it. Yes, usually he would want to get up to all kinds of things, but he's still a soldier at heart, and the night before a mission is when you focus, or things can go very badly, very quickly.

"For sleeping," he insists, with the air of 'I outrank you' even if it's just barely. That doesn't mean he doesn't plan to bring it up every chance he gets.