Well, that settles some things. While Crowley isn't against murdering kids, he can't kill them himself. That's just not who he is. So that takes that idea out of the equation. He can always tempt someone else to do it, but there's always the possibility that everything that this person says will happen will happen if she's killed, which would be horrific.

"Did they kill the last Lighthouse Keeper?" he asks. "Is that how she knows what will happen if you kill her?"

Crowley can understand not accepting consequences. He's never been the best at doing that, either.