Your story is the opposite of the Zimmerman story in that you were chasing but didn’t have a gun. Zimmerman was chasing and between the two had the only gun. The kid was always the hunted - IMHO.
Sounds as though Zimmerman got himself a Rambo complex. But as I’ve said before on this thread - we shall see. We don’t know all the facts yet.
you are right... and for better or worse, when anyone or thing feels threatened or hunted, survival response kicks in. That is why Zimmerman should have stopped, waited for backup... kept an eye out from distance.