[Myrddin]

SYG wasn't invoked. Besides, you can't very well retreat when flat on your back and straddled with an MMA style of punching pummeling your head into the concrete. It is defend yourself or die. Fortunately, Zim had a means of defense. He did call for help multiple times before Trayvon discovered the gun.

[bert]

Trayvon had a duty to retreat. Instead, he attacked and thus became a felonious criminal

He was not brought to trial because justice was done. He was dead