Sometime after midnight on July 6 two men walked out of the bathroom at O’Sheas. Words had been exchanged, and as the men continued into the food court one fired a single punch into the other’s jaw. The man fell. At 1:08 a.m. he was pronounced dead. The idea that one punch can kill someone seems crazy. We’re bombarded by movies where people take extended lickings and stand up for more. We watch boxers and MMA fighters go rounds—fists connecting with faces—without tapping out. But, says Dr. Tony Alamo, former chairman of the Nevada State Athletic Commission and a tactical physician for Metro’s SWAT bureau, a fight in the real world is a totally different beast. “You’re very capable of killing someone with one hit to the head,” Alamo says, citing brain bleeds, hematomas and broken bones protruding into the brain as possible causes of death. Most fights—let alone single blows—don’t turn deadly, but fatal strikes are perhaps not as rare as we’d like to believe. This week a trial begins over a fatal punch in Sioux City, Iowa, and this month, a 17-year-old Brit was sentenced in a killing that came down to a single blow. “Any fight can be a fatal one,” Alamo says—an important warning to the those on the receiving end of punches, and to those accustomed to throwing them, as well.