Arm chair warriors don't have the pertinent facts to make a decision in the fraction of a second that these situations require. Mistakes should be paid for, though not criminally unless there is reason to believe the officer(s) acted with criminal intent. Instantaneous decisions are often, if not always, required and people, no matter how well trained or experienced make unintended errors. Only courageous people can be expected to bring a succesful end to violent incidents, but they should not be second guessed by people with nothing to lose by being wrong. No might have beens, should have beens, or could have beens matter in the moment. The time for learning and teaching is not in that moment. Hope is truthfully the only useful emotion when the SHTF.