Later that evening, Meg and Pat argue about Pat’s account of his heroic past. Their dispute underscores the contentious nature of Irish history. Miss Gilchrist offers sanctimonious remarks about the prisoner, to which Meg responds curtly. Meanwhile, Leslie inquires why Pat has been captured. Pat and Meg quickly reply: a war is ongoing, and Leslie is a "prisoner of war." Leslie retorts angrily, asserting that his capture will have no impact on the British Government. He grows increasingly anxious about his safety, as it seems likely that the British government will refuse to negotiate with the IRA.

Pat begins to show more empathy towards the prisoner; he even joins the other characters in singing "When Irish Eyes Are Smiling" with Leslie. This moment of shared camaraderie signifies their recognition of the prisoner’s humanity and intensifies their worry about his impending execution. Behan highlights this acceptance through a surreal song-and-dance scene where Mulleady abandons his lover, Miss Gilchrist, to join Rio Rita and his transvestite partner, Princess Grace, in a song celebrating being "queer." (Later, it is revealed that all three men are actually undercover government agents preparing to rescue the hostage.) Leslie is about to partake in the song-and-dance routine but is stopped by a horrified Miss Gilchrist.

Following a minor scene transition, Teresa enters to find Leslie asleep. He is bitter about his looming execution and reacts hostilely toward her, but he becomes frightened when she begins to leave. They agree that if he escapes, she will visit him at his army barracks in Armagh. They are then interrupted by the IRA Officer. Suddenly, the British police storm the house. Mulleady reveals himself as a secret policeman. Amidst the chaos, Leslie is shot by British troops. The play concludes with a tragicomic lament sung by Leslie, who rises from the dead.