Shouldn't we hold police to a slightly higher standard than what random-sally-with-a-gun is expected to do? Isn't that the whole point of having police in the first place: that we trust them with powers we don't give to ourselves?

You're avoiding the point. "Reasonable officer" then. My point is that suspects aren't necessarily trying to kill when they give the police officer good reason to think that they are using unlawful force that that threatens someone's life.

And MY point is that you are applying the wrong standard. Law enforcement policy needs to be aimed at optimizing the net good to society and not making individual police officers feel safer. Because the standard you want leads to horrifying rates of false positives where people end up dying needlessly.