When my wife and I were training and competing in a tactical shooting sport we took advantage of all kinds of training and what would appear to be really odd tests. Many were from advanced skills tests done live fire against the clock for added stress. Frankly borrowed tests from SWAT and entry team squads. Also people yelling loud noises etc. Gotta say the kinds of mistakes that were made by even experienced students or instructors was compelling evidence for symptoms. Symptoms of stress like a massive adrenaline dump, tunnel vision, shaking, reduced fine motor control, Inured to pain. and more. Impaired Judgement .
Mistaking a gun for a taser looks and sounds more unlikely than one might think. All of this is exacerbated by a pursuit. By the understanding the public is at risk right that second. By way of the adrenaline and our ancient fight/flight physiology.

I guess my point is we have to keep a open mind and sharp understanding of the evidence at shootings before we judge. Heroism, justified shoot, mistaken, mishaps and malice are all possibilities.