One night in June 2016, in Orlando, Florida, an individual named Omar Mateen, acting on his own, seriously wounded 53 people and murdered 50 others in the Pulse, a gay nightclub. An additional two hundred or more terrified patrons managed to flee the packed premises while Mateen walked around knocking off his victims. How could he have done it? How could one terrorist, acting alone, kill or seriously wound a hundred people? Answer: he had a whole three hours, from 2:02 a.m. to 5:15 a.m., to stroll leisurely around the dance floor, hallways, drinking enclaves, and toilet stalls, killing people with casual impunity. Some of the patrons hid themselves for hours, repeatedly calling 911 or sending messages to friends and family, desperately pleading for help.