I remember commenting about intent on a previous post, I think maybe about knifes.

I basically said that the human phychology will employ the fight or flight mechanism.
If a humans life is in danger and the fight mechanism kicks in then that humans survival instincts may well prevail in a situation.
I also said that an attacker chooses to threaten life but a defender has no choice but to defend life.

So one is not considering there life at risk while the other is. Could the survival instinct to preserve life overpowering this attacker as the intentions are different?
That was not a skilled gun man, which I think took him by surprise and didn't want his life at risk so he fled....Flight or flight.