AN: This is just short of being a drabble and it's my first attempt at one. This is related to the season finale, so do not read unless you have seen it or just don't care about being spoiled. Please enjoy and tell me if you do so.
If Dean wasn't bleeding heavily on the floor staring up at him with that look, Sam would have taken the shot. No question, no hesitation. One shot it'd be dead. Dad was screaming at him to shoot. Neither party cared if he died, at least peace would be found.
What stopped his finger on the perfect trigger wasn't Dad's death. It was Dean's. Just because Dean's heart wasn't in the Colt's sight didn't mean it wouldn't destroy it.
Sam couldn't live knowing he killed Dean.
He lowered the gun.