"Imagine being in the infantry in Ramadi, like we were," he said, "where you get shot at every day and you get mortared where you live, [and attacked] with R.P.G.'s [rocket-propelled grenades], and people are dying and getting wounded and maimed every day. A lot of horrible things become acceptable."He spoke about a friend of his, a sniper, who he said had shot a child about 10 years old who was carrying an automatic weapon. "He realized it was a kid," said Sergeant Mejia. "The kid tried to get up. He shot him again."