Andrew bristles at Britomart's insistence on his fatherly duties, since the Undershaft tradition trumps the preservation of the family. Undershaft will have nothing of such obsolete "tricks of the governing class." As observed earlier, among Britomart's primary arms are those of class convention and her maternal authority. Britomart deploys these arms—as well as the memory of their marriage, perhaps—against her ex-husband's bombast. For example, when she plays the maternal wife and comically chastises Undershaft for his crooked tie, she reduces him to "childish grimaces." These familiar forms of domestic sociability present themselves as charming. They allow the audience to deflate and guard themselves against the hero's grandiloquent excesses as if they were the complaints of a child.

The subsequent exchange occurs between Undershaft and a self-important Stephen, dislodging Britomart from her place as head of the family. Stephen attempts to discuss his future with his father, as men must do. The comedy of their dialogue functions according to a principle of enumeration and accumulation. Undershaft lists a series of potential occupations and Stephen rejects each, revealing his uselessness to the world. While without talents or inclinations, Stephen firmly claims to know the difference between right and wrong. Undershaft makes his impetuous son's declaration to highlight the irony of the ideas of the moralists. He wonders how he can, like the Salvationists or politicians, be so sure they know the difference between good and evil.

The final major exchange occurs between Cusins, Barbara, and Undershaft, the poet, savior, and millionaire. Protesting Cusins's description of Percivale St. Andrews as a "Works Department of Hell," Undershaft begins to explain how he has brought his ideal community into being. Percivale St. Andrews runs on its own—its citizens preserve the social hierarchy and make any authoritarianism on his part unnecessary. As we will see, Undershaft's emphasis on hygiene and cleanliness will take on sinister proportions as well, though ones the play does not readily avow. Though the pair recoils in horror as they have done through, they will ultimately come to realize that Undershaft's gospel is the path to human salvation.