"Pretty sure I'd remember hiding a fool in my ass, so I probably don't." Most people wouldn't think to ask Lambert for a fool, but go straight to calling him one, so perhaps understandably confused when Childermass speaks. Of course, he has no idea what the hell he's talking about, but he's not going to say as much out loud, less it invite the other man's disdain (again).

"Then what are we waiting for?" He starts back off towards the door, glancing over his shoulder to make sure he's being followed. "You'll have to lead the way."

Yes, this would be him inviting himself to wherever Childermass' room is. And after a glance down -- "You can get your fool, and I can get some clothes on."