What is O’Brien’s purpose in including this story so late in the novel and immediately following “The Ghost Soldiers”?

The matter-of-fact language with which O’Brien recounts the events of “Night Life" creates distance. The reader is left to imagine whether O’Brien is sympathetic to his friend’s decision. Like so many other emotions in the book, the narrator does not explore this one outright. Detachment and simple language are key, and show the influence of Ernest Hemingway.