If it's the video they showed us in trainingwith a white pickup, the guy is in shorts, and cop asks the suspect to open a box in the bed of the truck, and the suspect is allowed to go into the cab of the truck and retrieve a box cutter to open the box - if it is that one, the cop shot him once in the stomach with a .45ACP.
What most versions of that video don't show is the interview with the cop, where the reason the cop gave for reholstering and fighting with the guy is he had lost confidence in his weapon when the BG didn't go down with one shot. He had been told so many times that .45s had great "stopping power," "would knock a man down," "if you shoot someone with a .45 and they're still standing, check to see what's holding them up," etc, etc, that he was shocked the guy didn't go down with one shot. He believed the hype instead of learning the reality.
Was it a mistake to let the guy get a knife to open the box? Sure, but the cop was human, and he was there and survived we weren't so don't be too harsh in the judgement. As for what happens after the attack with the knife and the shooting, the cop initially thought the guy wouldn't last long with a gut shot from a .45, but the BG keeps re-engaging, and won't stop fighting. Each time the cop has him down and tries to get his cuffs out the BG starts fighting again. Eventually another motorist came to help the cop. BTW, the cop did get some cuts from the knife so some of his difficulty with the suspect was a result of the initial attack. The BG survived the shooting.
It demonstrates a few things, 1- a handgun, in ANY caliber does not have "stopping power" unless you get a direct CNS hit, 2- Someone determined to fight can be VERY dangerous and difficult to restrain, even after injured severely.
Many will argue that the officer should have continued to use deadly force (his gun) to stop the threat. That is debateable, and armchair quaterbacking. The only thing that counts is he did what was necessary to survive.
EDIT TO ADD: Shep you added the additional description with the info about the coke, while I was typing. Based on that additional info I am fairly certain we are talking about the same incident.