It sounds more and more as if that man is a modern day Jekyll and Hyde, with Hyde considerably stronger than he should be. And what Caroline is saying is sinking in. If she levelled a bad at his head and he barely blinked, even Klaus's strength - in this state, anyway - is not going to do much.

"He doesn't mean to turn into the monster?" he checks, with raised eyebrows. A quick, clean kill if he does, before the monster can come out; an attempt at compulsion if he doesn't.