Undoubtedly there were a lot of mistakes that lead up to this point, better ways of controlling the situation — but it’s also easy to armchair quarterback. At the moment that Blake opened the door, cops have seen this exact scene in about a hundred different training videos. They are told that by the time they see and recognize a weapon, it’s already too late. There is a very strong culture of “it’s better to be judged by twelve than carried by six” among cops, the idea that their number one priority is to come home at night, the survival of the other party being optional.
When a cop tells you you’re under arrest, that’s it. That’s the end of the story. This isn’t bootlicking, it’s the truth. You don’t get to say “no I’m not” and walk away. Doesn’t matter how innocent you think you are; doesn’t matter how racist you think the cop is. You don’t have the legal right to veto your own arrest. Police can use force to arrest you if you resist; if force escalates to the point where there is a legitimate fear of death or serious bodily injury, they are legally authorized to use lethal force.