Dean does want to leave the motel. Wants it more than just about anything else he can think of. Except he's in no shape to drive and he knows it. He also suspects Cas is in no shape to drive either. Much as he wants to get out of this room, Dean isn't stupid enough to put them on the road when he knows they're as likely as each other to get into a wreck.

"I don't know if I can sleep." He rolls onto his side, throwing his arm over Cas' lap. It's an incredibly intimate motion, but it, like Cas' hand on his back earlier, is grounding. Dean can't make himself give it up. Not yet.