I agree...
I'll go even further to say that, in my very strong opinion...
GZ followed TM (even after he spoke with LE and was told that LE didn't need him to follow TM) because he did not want another "punk" to "get away"
IMO, Afraid that TM would indeed "get away," GZ caught up to TM, showed his gun, and tried to hold on to TM arm with the other hand to wait for LE...
IMO, this accounts for the brief period of TM (imo) calling for help, and then hitting GZ in an effort to get away...which led the scuffle and GZ shooting TM during the fight.
IMO, GZ did not follow TM so he could shoot him....but to physically hold him in place until LE arrived...
Imo, TM fought to defend himself and pumped up on adrenaline and having been hit himself, GZ felt justified in murdering him.
IMO, if GZ had let go of TM initially and let him go...TM would have run away.
IMO, and based on Rachel's testimony, all TM ever wanted was to get away from the creepy dude who was following him.