Honestly I think this is a poor situation and video to analyze as something to expect.
This video is relatively clear where mistakes are made, far clearer than in most situations.
A guy gets out of a vehicle and is severely non-compliant. He shows a strong willingness to be confrontational, and after running towards the officer, swears at him, flips him off and goes back to his vehicle.
All of this demonstrates that this guy has absolutely no desire to comply with instructions.
He does not get in his vehicle or try to flee but clearly is trying to retrieve something for several moments.
What that means is as soon as the guy retrieves a firearm there is a clear and immediate deadly threat by someone that has shown they are absolutely unwilling to follow any instructions.
There is really no need to even issue an additional instruction at that point and the officer should have began firing at the man right then, or after the first warning at the latest if he was inclined to issue one.
As soon as the guy who has shown he is hostile and uncooperative retrieves a firearm, never mind a rifle, it is time to put him down. We know the deputy realized he has a long gun because he tells him to put the gun down.
The reason this alone is a bad training video is most situations do not gradually progress so clearly.
So this gives an overly simplified situation to react to.
Keep in mind officers will encounter good people with firearms. Both open carrying, concealed carrying, and stored within the vehicle. As well as criminals that will not go for them or misuse them.
So someone simply having access to a firearm alone is not a good reason to shoot them.
It can be a reason for the officer to take precautions to be ready to use deadly force as soon as necessary though.
(But there is two sides to everything. Think to the open carry threads where the guy legally open carrying is dealt with at gunpoint.)
Here is another situation an officer faces, also in Georgia. I
n my opinion this video is a much better example of what to expect in a bad scenario. This officer survives, but only due to pure luck (criminal's gun jammed) and determination. This is deputy Steven Rankin:
http://www.youtube.com/watch?v=MEpUtoUzE4U
He is shot in the face approaching a vehicle in the dark before he even realizes a threat exists. Without any warning of noncooperation, or knowing a firearm will be involved. The criminal then gets out of the vehicle after shooting the officer in the face and attempts to execute him iwth additional shots. Fortunately for the officer in the state of Georgia they have not outlawed "Saturday night specials" or "junk handguns". So the criminal is using a piece of junk that jammed after the first shot, and he is unable to execute the defenseless officer sprawled out on the ground.
He then goes for the officer's gun to use it to finish him off, but by this time officer Rankin has started to partially recover some sense of what is going on, and fights with the criminal. Officer Rankin manages to both retain control of his own firearm and then later return fire when the suspect is trying to flee (which may have resulted in manslaughter or attempted murder charges for a non-officer at that point.) Of course as far as he knew those shots may have been the last thing he did before dying to his head wounds, and he wanted that criminal to pay as demonstrated by his own statement "I wanted him dead right then". He fired all 16 rounds from his weapon at the fleeing vehicle but the violent predator was not hit.
This is a much better video in demonstrating how quickly things happen and what to expect.
Most criminals are not going to demonstrate they are a threat in a lengthy manner before retrieving a firearm like in the first video. Training to expect for that to happen when it normally will not is in my opinion training for a "trigger" that may never come.
On the opposite end of the spectrum an officer pointing a gun at every potential threat increases the chance of the gun being pointed at someone during a negligent discharge.
Here is a negligent discharges by an officer:
http://www.youtube.com/watch?v=nDfNV9bJoSg
Now imagine that is you after being stopped and you are open or concealed carrying and the gun is pointed at you.
Or here is what appears to be a mistake:
http://www.youtube.com/watch?v=5bvWBN0IQCc
The officer on the driver's side says "reach in there and go ahead and get it". Presumably talking to the other officer near the passenger's side. However the criminal who ends up dead may have believed he was being told to 'reach in and get it'. An error in communication that cost him his life if so. Now imagine it was a good person with a firearm who made the same mistake or misunderstood commands or instructions being given to him, while commands are also being given to the other officer. Lights in his face unable to see gestures or who is talking to who, adrenaline pumping, one mistaken interpretation of a command and he is dead.
Now ask yourself if you want every uncomfortable cop with with their adrenaline high pointing a gun at you each time you are open carrying or concealed carrying and encounter them.
Keep in mind your suggestions to act a certain way anytime a gun is involved will involve such people as well as predatory criminals.
Being a cop is a tough job. But how tough a job should being a citizen exercising a right to carry a firearm be? The balance is not easy.