Yes, it's an admittedly smart ass answer in response to this: "I think it’s fair to expect trained police officers to be able to fire a round, wait 1-2 seconds and then reassess." I just get sick of these nonsensical "fixes" that aren't given any thought at all.
Your statement was completely devoid of how it would play out in the exact situation we are discussing. To apply your logic, let's assume that the officer shot this girl once and then sat back to "assess" the situation.... how much of an "assessment" is being done in 1-2 seconds? It would probably take longer than 1-2 seconds for the girl's body to drop to the ground. The officer would still be behind the girl and would still have minimal sight lines to the victim of the assault. What true assessment could be made?
What have you accomplished other than to increase the likelihood of the victim being hurt or killed in an effort to reduce the likelihood of the assailant being hurt or killed? I get that in a perfect world that no one would ever be killed by a police officer but in an actual perfect world, no one would ever attack someone with a knife.