Dean gives Castiel one of those looks he usually reserves for when Sam's being exceptionally obtuse. A tiny part of him is surprised by how easily he's accepted Castiel being right here this easily--then again, Dean's nothing if not adaptable, and he's had strange and uncomfortable allies more than once.

"Really. You've tried all that." Dean rolls his shoulders. So Cas has been fighting these things, too. Good. He should be fighting them. "Right. Let's slow down this son of a bitch."

Simple. In theory. And Dean, paragon of taking care of other people, even when he's really angry with them and would like to deck them, goes first.