He has a quiet conversation with Dean while Sam walks around the car, and later can't recall what the conversation was about. Nothing, maybe. It distracts Castiel from the pain he's in. That is, until he has to leave the car with Sam's help.

They're halfway to the door of the bunker when Castiel just stops walking. And standing still it becomes painfully obvious that his legs are shaking. He can't carry himself all the way right now, every step chafing, tearing, hurting.

And he can'T even remember the last time he ate, if he's perfectly honest.

"Can we... can we rest? Just a moment. I'll try again in a moment."