Yup, if she'd had the gun in her hand when they attacked her, or pulled it out while they were beating her she'd be good. But she walked away after the scuffle was over. Turned around and started shooting.No way her life was in danger. She had time to walk away and casually pull out her gun.
Initially I would have said a shooting was justified if she shot while on the ground. But that's not how it went down.
A life lost over nothing.