What if Dean left?
Dean came in the room slamming the door and started packing up his stuff.
"What are you doing, Dean. Leaving?" Sam asked.
"You don't need me, you have Ruby. You're a freak and the next time I see you I'm going to hunt you." Dean avoided Sam's hurt look and stomped back out the door.
His father had told him to save Sam or kill him. He had failed, but he didn't feel he could kill him now, but he meant what he said, so he sincerely hoped that he never saw Sam again.
The End