Barbara goes even further, grasping the underlying principle of life itself. For her, the ostensibly wicked Undershaft is not only essential to life as the master of reality, power, or salvation, but as the dialectical counterpart of goodness. In other words, the "way of life" lies through the "factory of death," the raising of hell to heaven and of man to God, and the "unveiling of an eternal light in the Valley of The Shadow." The work of salvation requires a pact with the Devil.

Cusins's failure to perceive the logic of this somewhat sophistic dialectic and the unity of life indicates his "middle-class morality." In contrast, as child of a foundling, Barbara has transcends social class and comes "straight out of the heart of the whole people," so she can serve as savior to all. Ironically, Barbara's proclamation denies the very class status that makes her Salvationist career possible. As revealed by her assault on Bill Walker in Act II, Barbara is not only compelling because of the inspiration she exudes, but the authority she wields in her aristocratic heritage, a class background that marks her polished speech and professional manner.

As with most conversion narratives, Barbara's epiphany requires the death of her prior incarnation—"Major Barbara will die with the colors," and her rebirth immediately follows. In one of the stranger moments of the play, the composed and eloquent Barbara becomes a child, calling for her mother and clinging to her skirts. This moment of the script seems particularly contingent on its staging. Interestingly, number of critics have identified the conclusion as a chilling one, a moment of terror. Undoubtedly the terror lies in Barbara's jarring emergence as a new being, an emergence that, in unmooring the underpinnings of the world, teeters on madness.