Controversial encounters between law-enforcement and civilians - the omnibus thread

I saw a particularly intelligent post in another thread:

How does this apply to “encounters between law-enforcement and civilians”? We have ample demonstration that some cops do not properly assess and avoid personal danger.
A very clear example is the Tamir Rice killing.:
Why couldn’t the cops have kept their guns holstered and made at least a token effort to hail the victim from several tens of yards away? The victim’s “weapon” was holstered and most insane psychopaths are not quick-draw sure-shots.

If one assumes that the cops in the Rice killing were thinking rationally, we must conclude they gave little weight to the victim’s survival.