I have always been told the if the situation presents itself and you end up pulling the trigger on someone (no matter where it is), you always say you were in fear of your life or harm to someone you are protecting. Once you say you were defending property, you are open to prosecution.
I feel bad for this lady, but she did the right thing. Of course she could have taken the guys knees out, but my gut tells me she didn't have much trigger time with the gun. If that is the case, and she is clearly scared, I would say you would tend to aim for the largest part of the target.