Mistakenly killed an innocent bystander in an empty parking lot 50 feet away from an empty campus police station? You've got to be kidding me. Also, you need to read the conclusion section carefully. "Although successful defensive gun uses occur each year, the probability of success may be low for civilian gun users in urban areas. Such users should reconsider their possession of guns or, at least, understand that regular possession necessitates careful safety countermeasures." In other words, proper training, which is required in Nevada to get a concealed weapons permit, has a direct impact on the probability of success in such an encounter. The study was also done in a high crime urban area. Reno, Nevada is hardly Philadelphia.