How the hell would you know with someone running at you like that? I don't think I would shoot someone in the back running away, but if I walked into my house and someone came running at me unexpectedly, even if they were yelling "don't shoot" I think I would probably have shot regardless of what they were yelling. That sounds crazy.
Maybe he didn’t fear for his life? But most reasonable people would have including me. Not too smart Bart! When my husband was a young police officer he saw a case where someone shot bullets into a horse lying in a street. One round ricocheted off the concrete and hit him in the head killing him. True Story.