I don't think that there was anything more than breathtaking stupidity involved.
All she had to do was walk down the hall and call her close-by police station on her cell and tell them she suspected possible armed dangerous intruders were inside her residence. Simple.
Would you enter your residence alone if you suspected this?
Not me!
How in the hell do you get into an apartment that isn’t yours?
Do you normally leave the door unlocked? Did the key even fit?
Does the interior arrangement look the same?
I strongly suspect this female officer isn't playing with a full deck, based on the fact most big city cops change their uniform into street clothes when off duty.
For a cop in this day and age, the last thing ya wanna do is go home in full uniform so every cop hating nutcake, gangster etc, can follow you and or watch which residence you go to. Very dumb thing to do.
Those who don't practice these common sense defensive measures are asking for big trouble and probably shouldn't be cops.
Negligent homicide is the same as manslaughter in most states although there can be different statutory nuances between the two. There can also be degrees of manslaughter, such as involuntary and voluntary.
I’d vote guilty on anything up to and including first degree murder.