The play portrays society as a machine, establishing a compelling metaphorical theme. In Machinal, Helen struggles against the pressures imposed by society. Treadwell uses sound and repetitive dialogue to highlight various stages in Helen’s life, characterized by repetition, noise, and an unseen, overwhelming force pushing her forward. In the opening office scene, human voices create an "office machine," and the world's sounds invade during her hospital visit. Helen cannot escape society's grip. Despite her efforts to resist, she is forced to assume every role within the machine—initially as a secretary, then as a wife, a sexual partner, and ultimately a mother. She detests each role and constantly feels pressured into submission. As a result, Helen never discovers a way to break free from the machine's control. In the end, her attempt to liberate herself by killing her husband is her first act of defiance against the machine. Almost immediately, society consumes her. The machine grinds her down and discards her when she refuses to conform. As Helen waits for her execution in the electric chair, the first reporter asks, “Suppose the machine shouldn’t work!” The second reporter responds, “It’ll work!—It always works!” These lines in the play's final moments complete the metaphor, showing that anyone who defies societal norms will be destroyed by its relentless gears.