The seeds of his volunteering were sown at the foot of Hindu Kush mountains in Afghanistan, said Chris Gill, who served as a staff sergeant with the U.S. Army’s 95th Infantry Division. A rocket attack in 2005 left Gill with injuries to his knees and shoulders, a painful reminder of his service at a forward operating base. “It’s difficult to explain if you haven’t been there,” he said, “but the thought of dying is present in the background every day. “My job in-country was to train Afghan soldiers in combat tactics,” Gill said. “It’s not nice what soldiers have to do. To say, ‘We’re going in and eliminate the targets,’ really means, ‘Kick in the door and kill everyone inside.’” Habits learned in war die hard, he said. “Every time there is a mission outside the wire [off base], you are scanning to the right and left for people who are on …