The complaint here is that Zimmerman wasn't arrested
I appreciate and respect your point of view and there are some valid points. Valid but debatable. I should not once again make this a personal biography but feel I should mention something I once experienced as a security guard. We were not armed in Canada.
I faced a man some 25 years younger and hard as nails. For one awful minute which seemed like an eternity, he made as if to smash my face. It was the last person out at close of the movie theatre. It came to nothing. Pacifist by nature myself, I believe I would have shot the man, had I had a gun and had he carried out his threats. He used body English.
The chill of abject fear, puts one on the side of self preservation- at any cost.
Fear for your life ~ when you've been ambushed and you are far enough away you take cover. The doctrine says if you are within the killing range no matter what you do the correct action is to attack!
Been that way since close quarters combat was invented.
Zimmerman should have realized he was hunting a human being, and that can always be dangerous. I suspect he thought Martin was going to duck into a friend's house ~