you realize everything about that 20-foot rule is assuming the cops don't already have weapons drawn and trained on the guy? in this case they were already aiming at him and he wasn't nearly close enough for them not to have time to squeeze a trigger. he wasn't charging at them either. if they want to use lethal force they should wait until he's actually close enough to do anything. "this guy has a knife and is kind of walking in our direction, lets shoot" is bad. anyone watching the video can tell they didn't need to shoot when they did. people who just WANT to support cops killing a guy have to go out and find mountains of bullfluff written by other cops that justifies shooting in a scenario that doesn't even fit with this one.