Most violent criminals act in the spur of the moment and don’t usually plan their crimes very thoroughly. The now-deceased Frank Taylor is a prime example of that. Like many criminals, Taylor had a history of crimes that range from drug-related charges to theft. But when he tried to rob a woman at gunpoint, he encountered someone who was well-trained in personal defense.  

Mid-summer in Glendale, Arizona, about 1 a.m. — a 4-foot, 11-inch tall woman walked to a Circle K gas...