By Col. Robert Hale’s count, Todd Nelson had already cheated death twice when he arrived at Brooke Army Medical Center in San Antonio. A 34-year-old senior logistics supervisor based in Kabul in Afghanistan, Staff Sgt. Nelson had escaped injury on hundreds of convoys by relying on speed, agility and a little luck. On a hot August day in 2007, a month before he was due to go home, his luck ran out.
Nelson and his partner, Chris Sanders, were headed back to camp when a Toyota Corolla pulled in front of their truck. Sanders hit the brakes and swerved to the left, then locked eyes with the car’s driver, who flipped a switch, blowing his car, and himself, to bits.
Sanders, shielded by Nelson, escaped with minor burns. Nelson took…