Thanks for the help guys.
I opened the console and enable God mode, killed that mob, then disabled God mode and went back inside.
I would have started the game again but the beginning of RPGs almost always sucks so I'm just gonna keep going.
I'm still not going to hard/quick save either. I was really enjoying getting my ass kicked, then reloading from the last auto-save and changing my tactics, avoiding that encounter/whatever.
I'm playing on GOG so I've no achievements to lose anyway. Thanks!