Prior Meets Birtwhistle
On his last night in England, before shipping out to France to fight again, Prior meets a friend of Manning's called Birtwhistle. He is a snob and angers Prior by nicknaming working class soldiers "WC"s which is verbal shorthand for "water closets" (toilets). Prior laments that Birtwhistle represents everything about England that is not worth fighting for, which is sadly ironic, as on his last night in the country he is putting his life at risk for, and fighting for, his final experience is with the representation of everything that is completely the opposite.
Manning and Prior's Closeness
Before Prior returns to France, he and Manning spend one last night together. They are physically very close to each other in bed but ironically have never been further apart, partly because of Prior's return to the battlefield, which is something that Manning would love to do but cannot, and partly because Manning gave Prior the opportunity of a desk job in London and a way to stay away from the fighting, but Prior did not take it.
Prior's Confidence in Rivers
What gives Prior confidence in Rivers as a psychologist is the fact that he does not sit behind a desk or try to set himself up as the gold standard of mental health care. This is ironic because all of these things are what give the majority of people confidence in their psychologist. Most people want to see someone behind a desk espousing knowledge and confirming that they know best. Rivers does not do this and the fact that inspires Prior's confidence is incredibly ironic.
Privacy versus Intimacy
Military dormitories and hospitals have the common characteristic of shared space that throws men together. There is no privacy at all but ironically this does not create intimacy, but the very opposite as men keep to themselves and try to keep sacred the limited amount of privacy they still have.
Headhunting as an Aphrodisiac
During his time in the south Pacific at a missionary village, Dr Rivers discovers that watching the village menfolk kill their enemies and "head hunt" - literally hunting for heads which they would bring back to the village atop a spear - was an aphrodisiac for the young women of the village. This fact is incredibly ironic, because usually women find that activities that stress caring and love are the ones that they find to be aphrodisiacs. It is unusual for slaughter and killing to be found to be aphrodisiacs.
