One morning, Billy is playing a hymn, "A Mighty Fortress Is Our God" (2.12.1), to the troops he's accompanying on maneuvers in the Carolinas.
An umpire comes by Billy's detachment and tells them that someone had reported their detachment killed by a theoretical enemy. The troops have a good laugh over being thought dead as they eat their lunch.
As Billy remembers this moment, he thinks over how much like the Tralfamadorian idea of death that had been: to eat and be dead at the same time.
Toward the end of maneuvers, Billy has to go home because his father is shot and killed in a hunting accident.