No, what it means is Z was carrying with full magazine and bullet in the chamber, gun on safety, manages to get gun out and off safety in struggle, pulls trigger once, gun fires and cycles another bullet into the chamber.
Trayvon slumps, so there you sit, right by the guy you just shot, and you are holding a gun with a live round in the chamber with cops on the way. What do you do?
Drop the magazine out of the gun, jack the live round out of the chamber, and put the round into the magazine, replace magazine into the gun, and you can then hand your gun over without having to hand over a gun with a live round in tne chamber to the officer.
That’s a lot of assumption there.
The plan to "hand over a gun" I think is a very bad plan. The officer has no way of knowing whether there is a chambered round or not. It won't matter because the officer will assume that the gun is ready to fire.
If you are ever in such a situation, I recommend that you drop the gun to the ground, in whatever state it is in after the incident, and, if necessary, stand on it while holding both hands up with fingers spread wide to show that you are not holding a weapon. As the police approach to take charge of the scene, you can walk several steps away from the gun so that it is nowhere near you if you are ordered to the ground.
If you leave the gun on you and an officer orders you to "drop the gun", I wouldn't be surprised if you ended up shot dead if you touch the gun.
I'd bet that the recent police shooting of a man coming out of a Las Vegas Costco probably went down that way; with one officer ordering the man to the ground and another ordering him to drop a holstered weapon. Touching the weapon, under the orders of one officer, would then prompt the other officer or officers to open fire.