Tucking her protectively beneath his chin, Sam continued stroking her hair. There was too much happening in the world for any human being to try and deal with it all at once. All he could do was take the step immediately in front of him--and right now, that was keeping Molly calm. Making sure she knew that she was not alone.
Life was full of split-second judgement calls, especially a life of fighting monsters. There wasn't a single hunter he knew who hadn't screwed up royally at some point. Let he who was without sin cast the first stone.
"Not even the devil himself can make me turn my back on the people I care about," he said. Coming from anybody else, a statement like that might have been mostly bravado, but for Sam, it was actually true.
And he realized, too, that he really was coming to care about this girl. "Trust me. If it turns out Harry's in trouble, we'll find a way to get him out again."