I don't play Fallout 2. Can someone explain what he is doing wrong?
You can just avoid the fight by stealing the key from the guy. Talking your way out can also work if you're character is build that way.
Fighting only really works when you've specialized in unarmed or melee and even then you shouldn't do aimed attacks.
The temple of trials isn't great design but you won't have trouble if you don't play like a retard.
There are at least 4 ways I can think of right now to get past that part. He's a boneheaded moron who went full DSP trying to do the same thing over and over again and not learning anything from his mistakes.
I think there was one that you were either so tough that he gives in to intimidation since you'd kill him, or there might be one for having less than 3 int where he just feels sorry for you