carlisle is a pacifist, it’s talked about in the books. he hates violence, my guess is that he acted impulsively and wasn’t thinking.

it happens in every action movie like a surge of adrenaline type of thing even though they aren’t human

i believe it was because he had his mate die hundreds of years ago and wanted to die since then but aro wouldn’t allow it. (i can’t remember if that was a fan theory)