Sam shrugged a bit. "She didn't want to spend her life as a monster. I knew how she felt back then. She asked me to do it for her, and it hurt a lot. Dean even offered to do it for me, but I couldn't let him. She trusted me."

He looked at Michael. "Sometimes it's not doing it because it's your job, but doing it because you care about that person and you're doing what's best."