First comes a chirping alarm over the PA system, then a woman’s lilting voice wafts over this dusty military camp: “Attention on the FOB, Attention on the FOB. Mustang blue. Mustang blue.” The tone belies the seriousness of the matter, which is that casualties are incoming and the Army’s 396th Combat Support Hospital team – “the Mustangs” – should be ready. The number of victims are color-coded: red for one, white for two, blue for three, and black for mass casualties.

US medics, nurses, doctors – and a chaplain – converge in interlocking tents that form the hospital, preparing for the arrival of three Afghan National Army soldiers injured when their vehicle rolled over an improvised explosive device. … Military chaplains