The 911 caller, which seems to have been “Scout” himself, said the person had both a gun and a knife. So you think in that situation the police are supposed to be able to read the perp’s mind and know every second what he will or won’t do?
It only takes a second or two to “open” a closed knife, and even if officers had any idea the blade was not yet exposed, they could not know the exact size of the weapon and it could be open at any second. A gun could be drawn from a pocket at any second. The distance between “Scout” and the officer who fired could be crossed in a couple of seconds max.
A friend of mine from high school was later stabbed to death (by her deranged boyfriend), it only took seconds from what I understand. I wish someone could have shot that guy before he took her life.
Anyone commenting adversely towards these cops, that hasn’t read up on the Tueller drill, is talking out of an orifice other than their mouth. You are spot on, in how fast things can go south with an attacker with a knife.