There were at least three armed cops standing behind her. Not one of them could have pulled her down from whatever she was climbing on?
Looks like the LEO are a bit down the stairs and out of the line of sight of the shooter, who upon hearing “Bust it Down!!” may have felt his life was in danger
https://theresistance.video/watch?id=5ff63502f23a18318ceb28a7
From what I have been able to piece together from various vids (I probably have not seen all of them) there were several police, some very heavily armed, mixed in with the crowd, some not far from the doorway. Not one seems to be in any way shape or form acting to defend that doorway or get between the protesters and the doorway.
If that doorway is such a "last line of defense", how come none of the heavy artillery is attempting to protect it? I find it hard to believe that crowd would have attempted to physically attack a hefty defense. Heck, the crowd (and the police we see on the crowd's side of the door) seem completely taken aback by one pistol(?) shot.
They were the ones leading her to the killing field. They had no orders to stop anyone.