Couple of scenarios to consider:
1- If Martin jumps out at Zimmerman, who seemingly was out looking for trouble, and is on top of him beating him down against the pavement and Zimmerman knows he has a gun strapped to his waist, would he be yelling for help?
2- If Zimmerman jumps out at Martin and is on top of him, who would be yelling for help?
3- If Martin and Zimmerman meet up and confront each other and Martin starts asking “Why are you following me” and they get into an argument and Zimmerman goes for his gun and Martin grabs him in an effort to prevent getting shot (and they start “scuffling” like the witnesses said), would Martin start yelling for help then? I dont think Zimmerman would start yelling.
Zimmerman was out to play Dirty Harry, he felt in control and macho with his gun packin. Would he lower his sense of macho-ism, let Martin get the better of him, and then start asking for help at the top of his lungs?? It doesnt sound right to me. Something wrong with that scenario.
More likely, I do believe, Zimmerman brought the gun out into play, or flashed it to Martin, and the scuffle ensued in Martin’s attempt for self-defence, followed immediately by his screams for help knowing he was up against a gun and there were people all around them. Seems logical. It also seems logical that Zimmerman reached for his gun and maybe even without pulling it out of its holster just turned it towards Martin’s chest and fired.