His biggest fear is being alone, right? Seeing everyone around him die. And in this episode, he faced the possibility (or the reality) of the three people he truly cares about being gone. Cas is gone, for all he knows Bobby is gone and in that ambulance, he was facing done the possibility of Sammy leaving too.
Dean Winchester you deserve the biggest hug in the entire world.
EVERYTHING ON MY DASH IS THE EPIC LOVE STORY OF SAM AND DEAN AND I WOULDN'T HAVE IT ANY OTHER WAY. I'M FOLLOWING THE RIGHT PEOPLE. I FUCKING LOVE YOU ALL. NOW IM GOING TO CRY SOME MORE. BECAUSE IT HURTS.