Irrelevant. In a life or death situation panicked shooting will occur. You can miss the charging target even at point blank range. Inside of 30 feet I would consider a knife wielding person as a threat to my life even if I was already drawn down on them.
21 feet.
If he gets within that range, the officer is dead.
That's 21 feet from the draw. Not aiming down the sights.
Irrelevant. In a life or death situation panicked shooting will occur. You can miss the charging target even at point blank range. Inside of 30 feet I would consider a knife wielding person as a threat to my life even if I was already drawn down on them.