There's a 21-feet distance supposedly required for a trained shooter to draw and fire a gun before a knife attacker can close in. Sure, they had guns drawn, but you still cannot "wait" until they approach.
And, frankly, this "didn't need to die" perspective is alien to me, and I bet most people. If it was my life on the line, I wouldn't even allow a 1% increase in risk - the guy readying to, and obviously willing to, attack someone with a knife deserves to die. Does he "need" to die? No. Maybe event if he's literally in the process of stabbing someone, it would be wonderful if we could freeze time and just take him to a mental ward. But is it acceptable for him to be killed? Without a shred of doubt, yes.
But.... they were pursuing him! They chose the distance! If they weren't able to safely stop him because they were too close and had to kill him if he stopped (because let's be honest here: they killed the guy because he stopped)...
Isn't that STILL a failure of policing? It's it STILL true that he didn't need to die? Why were the cops' "lives on the line" if they were the ones choosing to engage?
They were not the ones initially choosing to engage. I wouldn't expect them to have sound judgment or impartiality after they were attacked in the first place and fired at with a taser. Again, he absolutely didn't need to die, but he totally deserved it and the cops' reaction is understandable. If I ever attack a cop, wrestle his taser off of him, and fire at him as I run away, I'd like to, in advance, absolve the cop of all responsibility of shooting me in the back. I understand he wouldn't quote need unquote to do it, but it is totally acceptable if he does.
And, frankly, this "didn't need to die" perspective is alien to me, and I bet most people. If it was my life on the line, I wouldn't even allow a 1% increase in risk - the guy readying to, and obviously willing to, attack someone with a knife deserves to die. Does he "need" to die? No. Maybe event if he's literally in the process of stabbing someone, it would be wonderful if we could freeze time and just take him to a mental ward. But is it acceptable for him to be killed? Without a shred of doubt, yes.