Gun Control & RKBA

Watching that video, the mom is not vicious or going out of her way to harm the perpetrator. In self-defense situations, you shoot until the threat is stopped or the gun is empty. In this case, the latter outcome happened first, and the assailant was then able to grab the gun, pistol whip the mom, and then try to shoot the daughter (but the gun was empty).

There's no point in going too deep down "would have" rabbit holes, but all evidence in the video points toward the mother handling the firearm competently enough to keep possession of it until it was empty. And once the gun was out of the equation, the assailant's larger mass, greater strength, and viciousness became the dominant factors.

-app