Why does the war end? How does Dunny respond to the war’s end?

Germany was defeated and forced to sign an armistice. Dunny travels to London but finds the festivities too much like battle:too loud and too much stimulation.

But I saw some of the excitement and a few things that shocked me; people, having been delivered from destruction, became horribly destructive themselves; people, having been delivered from license and riot, pawed and mauled and shouted dirty phrases in the streets.