What difference does it make?
What matters is whether GZ thought his life was in danger.
In the position he was in, St. Skittles could have whipped out a knife and dispatched GZ in less than a second.
Z had no idea what his attacker was packing.
Z knew that T saw the pistol and was going for it. I think that was when Z really knew he had to defend his own life. Z was carrying a little Keltech, hardly the weapon of a Vigilante Racist.