Erica: Ok I'm ready

Crowley whistles for the hellhound.
Erica's body drops to the ground fool of blood then Dean and Sam come in to see Erica dead.

Dean: No
Sam: Erica come on wake up
Dean: ERICA !!!

Erica's spirit is with Crowley

Crowley: You ready darling?
Erica: Yeah I am ready
Crowley: Follow me then

Erica goes with Crowley