In all seriousness (i.e. this is not meant as a snarky, polemic), if you really want to explore the point, I suggest asking a cop. Department policies actually differ from jurisdiction to jurisdiction, but in general, most are written such that an officer who legitimately fears for his/her life, or for the lives of others, is considered justified in using deadly force.

And again, this is a very different situation than one in which you've got someone barricaded inside a house negotiating through the window. The risk in this case is real and immediate.

Incidentally, we are, in fact, talking about a real-life situation, and per policy, the FAMs were absolved of any wrongdoing because they acted properly. Unfortunately, the fact that an "innocent" man died is not proof that something was done wrong by the FAMs. It doesn't work that way.