“What do you expect when cops are practically given a free hand in such situations?”
Her defense will be that she acted in accordance with departmental guidelines and her training. Video training simulations are fairly common and routinely teach cops to act instantly when a threat is perceived.
I suspect that the innocent act of just opening the door was a threat to this officer.
So the best way to handle it is never open the door if it's a police officer.
Judges need to make clear that "I was only following training" is not a defense in cases like this. More to the point, making that statement should ALSO trigger an indictment of her trainer.
Then no citizen is safe, anywhere. Even in his own bed.