Sam got severely hurt in a hunt and Dean was desperate, he didn't knew what to do. Untill you came out of nowhere and made him more stressed out. "oh great now, reaper time? Seriously? I can't let him die now, i need him." Dean said to you, you were just walking closer to see Sam there, he was almost dying. It was your choice, let him live or die. Sure Dean was going to try and convince you to let him live and you're not gonna lie, you find the brothers to be quite adorable and amusing.