I wasn't. It wasn't attacking me.

( it was threatening someone else, and damn it, that almost sounds valiant!! NOoOOoo this is a sin, damn it!!! )

I don't think so, but I don't know for sure. It doesn't change that I used more force than necessary on a creature that was not intentionally hostile. Or that I chose to go back to violence, when I know that's what brought me here.