In other words, one of the deputies shouted "gun", so they killed her. Maybe like you said, negligent discharge. Surprised they didn't have a "throwdown" gun handy. I wonder if she was even involved in the car theft? They never make that connection in the police press release. They say, "nothing good happens after midnight". But we all know that's where the fun is. Until the police show up...
During the contact, deputies were alerted that the suspect had some remaining Constitutional rights, so the suspect was fatally shot.