What if Sam couldn't get in the panic room because of the demon blood?
"Thanks for getting here so fast, why don't you go in. I wanna show you something," Bobby said, indicating the panic room.
Dean and Bobby hung back so they could lock Sam in. Sam stopped at the edge. "I can't."
"Why not?" Bobby asked.
"It's like there's an invisible force field."
"Must be the demon blood," Dean said.
"What now?" Bobby asked.
"Can't you get whatever it was you wanted to show us and bring it out here?" Sam asked.
Dean and Bobby exchanged a look that told Sam everything. He pushed Bobby into Dean and ran out into the night.
The End