Knowing that she had dialed 911 and that officers were inbound she fired blindly out a window of her home trying to "scare off" what she thought was a prowler. She didn't put her glasses on or her hearing aid in first. It's amazing she didn't shoot one of the officers.
I'm inclined to believe she had decided to take matters into her own hands and exited the house fully intending to put lead into somebody.
It's unfortunate, and I know her family is hurting, but it sounds like the LEO's responded to the best of their ability.