Obviously they are in the fight or flight scenario, so as such running away can be seen in the same context as running towards. Therefore they are threatening whoever they are running away from as much as if they were running towards. The only way to effectively prevent this cycle of threat is to stop the initiator of menace from moving at all, and the most effective method to do so is to kill them.
Any movement towards, away, in circles or waving arms and shouting/not shouting can be safely regarded as the same level of threat. However also be aware that no movement whatsoever can be extremely threatening as they are obviously thinking how to hurt you, preventive action is advised.
Killing, in the absence of video cameras allows for arrangement of the scene as need be and has the advantage that only one side of the story being available. If the terrorizer has a criminal record, or is suspected of anything at all, so much the better. You can rely on the media, especially if this violent criminal threatening the upstanding law enforcement officer is not white. This applies also to self appointed vigilantes claiming stand your ground rights.
Is it too early for snark? Just seeing that officer casually kill then try and arrange the scene was surreal. It brings into doubt all similar police actions and incident reports, without the video, we can only assume the worst.