I think Zimmerman acted in self defence and should have been acquitted. But if I recall there it was 2nd degree murder or nothing, no lower charges available to the jury.
Premeditiation here? Murder 3 seems like a layup. I don't think he has an obligation to provide medical assistance, but, and these are if's for now, another LEO told him he had no pulse, and a bystander told him something similar. And he was motionless for minutes after being combative. And for propriety I'll simply say he discharged fluid, if the LEO contends, we haven't heard from him, he had no idea the victim was in distress, I think he's lying. So maybe I could be convinced. I say maybe largely because I wonder if the prosecutor has knowledge dictating a lesser charge. Not a lawyer, but I believe in most states depraved indifference will support murder 2, which in my unprofessional opinion is probably the better charge.
It's all on a single continuous unedited uncut video from someone's phone taken in real time as it happened from six feet away.