I was able to have my gun on him the whole time, as he was running. These people and the unarmed guy (Dick Peterson) killed one of our friends, which was why i shot him.
The player ran in and saw you standing there, he instantly turns around and runs off unaware you are even following him, I see no speech coming from yourself from your evidence indicating you said nothing at all to him (Stop, get on the ground etc) This all happens within three seconds and because you have said nothing he believes he isn't at gunpoint.
He only gets a brief glance at someone moving towards him and turns away to run off, if you had said something like get down etc this would be a different result but you didn't.