On October 16, 1991, a man drove his 1987 Ford Ranger pickup truck through the front window of a Luby's Cafeteria in Killeen, Texas, yelled "This is what Bell County has done to me!", then opened fire on the restaurant's patrons and staff with a Glock 17 pistol and later a Ruger P89. About 80 people were in the restaurant at the time. He stalked, shot, and killed 23 people and wounded another 20 before committing suicide.
During the shooting, he approached Suzanna Gratia Hupp and her parents. Hupp had actually brought a handgun to the Luby's Cafeteria that day, but had left it in her vehicle due to the laws in force at the time, forbidding citizens from carrying firearms. According to her later testimony in favor of Missouri's HB-1720 bill[1] and in general, after she realized that her firearm was not in her purse, but "a hundred feet away in [her] car." Her father charged at the gunman in an attempt to subdue him, only to be gunned down; a short time later, her mother was also shot and killed.
Hupp later expressed regret for abiding by the law in question by leaving her firearm in her car, rather than keeping it on her person. This video is her testimony.
Thanks to esteemed KFAB Listener Daniel F. for passing it along.