The strangest thing about that video is how he walked up to them with the gun drawn and pointing at the reporter, who looked at him, and neither she nor the interview subject noticed anything unusual. That’s a strong argument for having a bit of situational awareness.
I've heard two possible explanations. One is that there was a light set-up on the camera that would have caused vision issues as Miss Parker turned toward the camera, then the shooter. The other is that reporters are trained to ignore bystanders to get the interviews done. Both are plausible.
The light from the camera appears to be visible in the middle image from post 13 above, as both the reporter and interviewee appear to have extra light shining on them which I doubt can be fully attributed to muzzle flash.
***This can't be happening. This can't be happening to me!***
[famous last words.]