Wish he could say it's a relief when Cas responds, when he confirms Dean's eyes aren't just screwing with him, but —

"Why do you look like microwaved death?"

Cas is an angel, shouldn't he be above whatever's doing this? What the hell are they gonna do if Jimmy starts falling apart on them? It's not like there's an abundance of Novak running around as an alternative, and even if there were, signing up some other poor bastard to house an angel is just... No. It's a huge nope.

An undead lurches forward. A hand shoots out on instinct, and Dean blasts it (along with two or three more from behind it) back a dozen yards in a pulse of white light.