One of the first things you learn in a home defense class is to make a plan. One that takes certain things into consideration. One of the first is the reality that if you shoot at somebody in your home in the dark you are most likely shooting at somebody who is supposed to be there. So you make a plan and run through it in your mind. Where should everybody be? How do you get there to verify? What is the pattern of the rooms? If you can't check everybody before you find somebody approaching you make sure your family knows the pattern and that you will ask and expect to be answered "Who are you?" and why.
First part in to perspective. If I have time I would hit speed dial and ask my daughter where she is as I grabbed my gun... The phone is by my bed, in fact it sits on top of the gun safe attached to the wall. It serves well as a bed stand. I put it there so I would have access to my phone as part of my plan. I know that one person is outside of the house... Of course she would likely turn on the lights if she came home, but what if she's trying not to wake anybody? Should I shoot her because, like at USF's house, she would be walking in the dark?
If the intruder hears me talking on the phone it is again too late. They already know I'm awake, the dogs in the room barking would be a dead giveaway... it isn't going to hurt for them to know I'm talking on the phone to somebody and that I want to know where they are.
Stop playing stupid, man. Seriously. I'm done with this, it's the stupidest conversation I've ever held on here. In your opinion her only option was to open fire without knowing if the person she was shooting at belonged in the home. That's stupid. It was stupid then, it caused a tragedy, it would be stupid at my house, your house and every house.
And you. Specifically you. Who is too stupid to take a home defense class and learn to prepare. Should never keep a gun in your house because you think anybody approaching you in your home in the dark needs to be shot and that there is no way to prepare or make a contingency plan or even a way to find out if they are somebody you don't actually want to shoot. Your family is in great danger, sell your guns today.