It sounds like a pretty complicated set of events that could have gone a whole bunch of different ways. My soon-to-graduate college son won't shy away from an argument, but is also a bit naive. I keep warning him about “the real world”. And how stuff like this can spin out of control
Sounds like Epps instigated the argument with the several drive-bys and yelling. And that provoked Walker into throwing a fist. And Epps then shot Walker in self-defense.
If I had been Lee, and watched my relative just get shot, in the heat of the moment I would not wait for Epps to point his gun at me and then try to draw mine. Mine would be out the moment my relative (or friend) was shot. I suppose I would be in the wrong, but it would be survival instinct. (Although I wouldn't have stood over Epps and kept shooting him while he was down as some witnesses have said).
The best thing of course is to avoid these situations. (Of which I'm trying to teach my son.) I would have done everything I could to keep my relative from going out into the street in the first place. Call the cops after the second time they drove by. (I'm not too bothered with my "street cred" going down by calling the cops!) Although where I live the cops would be here in a few minutes with two or three squad cars. I'm guessing where these guys live the response would be “So your saying a car had driven by your house yelling things at you? And you want us to do what!?”
“Sounds like Epps instigated the argument with the several drive-bys and yelling. And that provoked Walker into throwing a fist.”
Reset occurs when Epps drives off and defendant and partner go down the road to confront and attack Epps.