Maybe zombies attack again. Maybe Dean runs out of ammunition, and all he can do is take refuge in a closet again. Maybe Sammy and Garth (Garth, because there always needs to be more Garth) arrive just in time, killing many a zombie. Once everything’s calm, maybe Sammy knocks on the closet door.
Sam: Dean? It’s alright, you can come out of the closet.
Dean: … shut up, Sam.
I’m sorry, I can’t help but think things.