I know that the prosecution is trying to assert that it wasn't possible for George to both be smothered and scream at the same time, based on his accounts of that night.
Here's something to consider... John Good testifies to seeing the fight on the grass first, and then it moves up to the concrete. It's totally plausible to me that when Trayvon got George on the ground in the grass, he immediately covered his mouth and nose putting George in to a panic.
From there, it moved up to the side walk where Trayvon grabbed his head and started putting it against pavement, opening up the opportunity for George to start screaming at that point. If they were relatively low to the ground, and George was struggling in response, his head injuries may not have been severe as opposed to somebody who is standing upright and gets thrown to the ground on concrete. So the fact that the cuts to the back of the head are not severe, indicates to me that potentially his head was thrashing back and forth on the pavement or being knocked from a close distance from the ground. He did have abrasions/rash-like injuries as well as the two open cuts.
The fact that George can't remember the sequence from exact moment to exact moment is not rare. People in these circumstances usually are not able to say the precise way everything happened, especially when it happens in a very short time frame.
In my opinion, it's totally plausible that he was briefly smothered, creating panic, and then the head on pavement and Trayvon's hands near his gun pushed him over the edge, as far as fear is concerned.
The prosecution's argument that he couldn't have had the opportunity to scream doesn't work for me.
IMO