That’s a pretty good video of the shooting. Starting at about -1:20. Shows the shooter (long rifle) running away from one guy chasing him - I presume the chaser is the guy shot in the head.
Then comes the armed guy with the medical bag and is on the phone (other video shows better). But he runs off.
Not a medical bag he is the shooter. He runs up and you hear the shots ring out. Then he backs up and the streamer does a close up and you see him standing over one of the victims on his phone but do not see his face. Below him an Antifa guy has taken off his helmet on the ground at the shooters feet and his shirt to give aid to one of the shooting victims. Than he casually turns around and then runs off. People begin to come from the left and shout to chase him down. A few seconds later you hear more shots ring out. The Antifa guy helping the victim on the ground with his shirt off ignores the shooter even though he is standing right next to him.