Self defense from the person that was standing in the apartment she forced herself into? Tell me more about how that works. I don’t see how that’s mistaken self defense at all. Intent cannot ever be judged by a jury.
You don't see how her mistakenly thinking she was in her apartment and faced with an intruder is mistaken self defense? And intent is always as far as I know judged by a jury (or other fact finder). Even if there is a standard for intent that imputes intent based purely on certain factual details, it's still the jury or fact finder applying that standard.
And if her intent was so badly altered by the number of hours she worked that day, then she was so poorly trained and equipped to handle the normal duties of her day job that the police department ought to be embarrassed that they ever handed her a badge and a gun in the first place (and possibly even civilly liable). But that’s another story. The facts are she forced herself into someone else’s residence
By forced, do you mean opened an unlocked door? Or did she actually have to break in? If she actually had to jimmy the lock so something to get in, it starts to get hard to believe there wasn't something else going on.
and shot them dead, without provocation. By very definition, that is murder at best and capital murder at worst,
That's not all there is to the definition of murder. it might be clearly murder under texas law. Or they might have interpreted malice aforethought to not include mistakes, even egregious mistakes. For example, let's say a cop comes upon a man ontop of a woman holding a knife, and the man is forcing the woman's wrist and knife back towards the woman, coming close to her throat. The cop shoots the man and kills him. Unbeknownst to the cop, the woman was having a psychotic break and attacked the man, adn the man was just trying to subdue her. Is that murder? I think it probably wouldn't be but have no clue. Does it matter if the cop is off duty? Also no clue. Or if it's not a cop but just a civilian that thinks he/she is being a good samaritan and stopping a murder?
depending on if Texas regards breaking and entering as a felony.
usually I think to be a felony it is required for their to be some intent to commit a crime inside.
It’s not like she was texting and driving and accidentally struck a pedestrian. She deliberately pulled out a device intended to do nothing but kill people, and used it deliberately (and again, without provocation) for its exact intended purpose.
And she probably committed murder but possibly committed manslaughter. Manslaughter may be less than she deserves, but if she were to get say 15 years for manslaughter, I don't think it'd quite be a miscarriage of justice, or at the very least, would be way down the list of them that occur pretty regularly.