The problem isn't what you don't know, it's what you know that just isn't so.
There is an old saying that the safest place for a ship is in harbor, but ships are not built to remain in harbor.
The same goes here. A policeman's #1 job should not be to keep themselves as safe as possible, it should be to protect and to serve. This mindset that it should be #1 to remain safe is why police remain outside during mass shootings, shoot people sleeping on train platforms and why they kill people with knives who could otherwise be subdued.
The idea that you should not take undue risk acknowledges that certain risk is to be taken.
This woman was paranoid schizophrenic and the police knew it. She was acting bizarre. The neighbors called the police because she was acting in a threatening manner. But instead of coming prepared to deal with the woman in a non-lethal manner, they appeared to expect her to act in a rational manner and then shot her when she acted in a manner that the neighbors had been complaining about. Why did they send four cops? One cop could shoot a 52 year old woman? They needed to be prepared to subdue a paranoid schizophrenic and Baker Act her. This woman was evil, she was sick. Sadly the police in this incident acted in such a manner that shooting her five times seemed reasonable. Does that department not have tazers or shotguns with nonlethals? A rational person would of course not attack four armed policeman. They relied on this as a logical defense, but it was illogical because they knew that she was not rational. You will say that the situation didn't allow time for nonlethals or whatever, but they created the situation and were in charge of it from the very beginning.