Police are trained and supposed to take that non-lethal force chance, yes absolutely. I am personally not a cop, because I don't want to be in those situations. But people that DO sign up to serve and protect the public should be held to a higher standard than the general public, especially considering the tools, training, and resources (money) police forces have at their disposal.

You're not going to convince me the only way to safely end this altercation was by shooting the mentally ill man to death. We have to ask ourselves how we can do better so we can learn from these situations and less people die violent deaths.

To use your your logic: why do tranquilizers even get produced at all then? Why don't we just shoot every unruly animal? Wild and sick animals are just as or more dangerous than a man with a knife on a stick.