I have some doubt as to the true events in that the woman claims she was aiming at the perps legs.
I have a life long friend that used to be the Director of Firearms Instruction for all the police academies of a particular state. He also did training and instruction for those civilian women that desired to be CCW holders. He would teach women to aim their guns at a male's family jewels as it apparently made more of an impact on a perp than having a gun aimed at any other part of the anatomy. With this in mind, I would have to think that in the heat of moment with the adrenaline pumping, this woman probably was doing something like that except with trembling hands, hit the perp in the legs where he bleed out because of a lucky shot hitting him in a major artery.
Then again, maybe she did aim for the legs?
May the Schwartz Be With You.