Zimmerman was given first aid at the scene. There will be first hand information about his injuries.
As far as Martin, his objective was to take out Zimmerman with a single blow. In this case Zimmerman’s nose took most of the shock. Once you start bleeding from the nose, it is very hard to breathe and it is very hard to fight. If Martin was on top, the most Zimmerman could do was get off the concrete so his head would hit grass as Martin bashed his head. Unfortunately, the squirming also revealed the concealed 9 mm. That is where I speculate a battle for the control of the gun was initiated. No injuries to Martin in this scuffle for the gun. However, when the gun went off, any further injuries would have ended. My speculation says that Martin received minimal injuries.
When I was younger, two of my classmates got in a baseball bat fight on the school’s baseball field. One of them got his nose broke with a baseball bat. He bled violently but was able to get the bleeding to stop. This is what I believe took place with Zimmerman. The first aid was able to control the bleeding and those videos at the police station would not have shown the blood from the nose like everyone expected. However, the enhanced ABC News video did show the gashes on the head.
And you know this how? I read a report that it was a KelTec. There are two KelTec 9mm models, the PF9 and the P11. I have a PF9, it fits in a pocket, but if worn inside the waistband, even pulling up the shirt would probably not reveal it in any obvious way. I speculate, and it is speculation, that Zimmerman was in fear of his life, or great bodily injury, accessed the pistol, and lawfully shot his attacker.
But the evidence will show if the shot was fired at contact or near contact range, where exactly the bullet entered, and where it came out, if it did.
Alternatively, Martin abruptly confronted (legally) Zimmerman, who reacted (reasonably and legally) by drawing his weapon.
In (reasonable) fear for his life when a strange man draws a gun on him, Martin jumps Zimmerman (in legitimate self-defense) and attempts to obtain control of the weapon.
During the frantic struggle over the gun it goes off and Martin dies.
Under this scenario neither party behaved illegally in any way. It is every bit as feasible as yours. If Martin had been the survivor he could have legitimately claimed self-defense.
I don’t claim that it IS what happened because I just don’t know.
There is of course a third option in which Zimmerman assaulted Martin then brought the gun into play when he started losing. In which case self-defense wouldn’t apply.