I took two major lessons from that video.
1. Control your scene. When dealing with people first I ask for compliance. If that doesn't work, they get told what to do with an explanation as to the consequences of further non compliance if necessary. I am usually laid back and will take the time to talk people down, but that only goes if I feel like the situation is improving and not escalating. If things are still not going the way I want it to after that then it is time to act and act decisively. I choose a course of action that I am 100% certain that I am justified in taking so there is no hesitation on my part.
The physical fight should have started, at a minimum, when the subject charged the officer. Using 20/20 hindsight, that would have prevented the rifle from coming into play, but also it would have helped take back the initiative, stopping the subject from dictating the course of action.
2. Commitment to the use of force. Once you make the realization that you are fighting against a deadly threat, respond with your own attack using overwhelming violence. Do not de-escalate until the situation calls for it (which would be when you are fully in control).