At the beginning that video appears to be from a dashcam, perhaps when he first pull up (?). It doesn’t have timestamps, either. Interesting.
Edit: You can hear shots 1-9 at the start, so that must be from when he went back into his vehicle to get his rifle. Yet this mashup video shows him running to his vehicle just after the shots are fired, to retrieve his rifle. His dashcam video must have been running the whole time. Hmm.