It's all about optics, one side says the perp got what he deserved, the other will say the force and final shots were excessive. It's going to be in the hands of the 12 people that will decide what the shooter's fate is.Again, no one is disputing that self-defense is not permitted nor illegal, or that he didn't have the right to protect himself, but the whole problem is with the propriety of that last Coup de Gracie shot directly to the perps head. If/when he goes to prison, that last shot, will be the reason why.
As a gun person even I felt like the last shots were excessive, no idea what prompted the shooter to do that, I've never been in a situation like that, and can't know how I would react.
As far as leaving I can absolutely see why he did it, that last thing you want to do is answer questions after a stressful event like that. Unfortunately "I want my Lawyer" will still lead to questions asking you about what happened by LEO. I would rather have time to select a good attorney, time to unpack what happened, and then interact with those that will be trying to find me guilty. The optics of leaving though will fuel the fire of those that think what he did is wrong.