If I recall the story correctly, she lost both her mother and her father in that attack. She left her gun in her truck because of the carry law that was in effect at the time. Again, if I'm not mistaken, it was legal for her to carry in her car but not outside of it.
She went on to become a Texas legislator and headed up the effort to institute their new concealed carry law. I believe her name is Suzanne Gratia-Hupp or something close to that.
From Wiki:
It should be noted that many of the patrons, such as Suzanna Hupp, had firearms in their vehicles but by law were not allowed to carry them on their person. Survivors and family of the victims, with the help of the media, were successful in moving lawmakers to consider the concept of conceal carry permits for citizens. As a direct result of this massacre, in 1995 Texas lawmakers, led by Suzanna Gratia Hupp (whose parents were both killed in the massacre), passed a law that allowed Texas citizens to obtain a concealed carry handgun permit in part as a reaction against the massacre. Soon after many states considered similar weapon permits for lawful citizens.
Too bad it takes an event like that to let citizens carry their weapons. The data still proves CCW states have less violent crime of this type even though the lefties try to bake it other ways.