Hard to answer, without more details...
HOW are you threatened with violence by this stranger, if he had no gun or knife or any visible arm?
WHAT made him irrational, in your opinion?
How big was he compared to you (or me), if the threat of violence through a fist fight was the fear?
Could you, (or I) just leave?
For me, it's hard to answer these type of questions like yours in the op, because in a real life scenario, there are so many other things that shoot through ones own mind in evaluating the situation that just a simple sentence or two, describing it, doesn't account for... like with your op.
In other words, I would trust (and do trust in real life), my own instinct and evaluation of the situation.... if my gut told me that I truly was in danger, I'd shoot him somewhere, that wouldn't kill him...
If I thought I could get away from this violent person and not be mutilated, I'd do that...
I just think you have to really be there, to size up the situation... no answer given here by anyone, is a guaranteed answer for what really could or would happen, if you are there, in person with all your senses flying high.