Mary Debenham arrives with her “head thrown back as if in defiance.” Her appearance “suggested the figure-head of a ship plunging gallantly into a rough sea.” Poirot confronts her with the information that she lived with the Armstrongs at the time of Daisy’s murder. Mary flinches before recovering and admitting the lie.
The image of Mary Debenham as the figurehead of a ship captures both her “defiance” and her essential helplessness, driven forward as a ship is driven by the wind. Even knowing that Poirot is getting closer to the truth, the revelation of her lie about her presence at the Armstrongs shakes her.
Mary attributes the lie to a desire to escape scandal so that she could find further employment as a governess. Poirot asks how she could not have recognized Countess Andrenyi when she had lived with her. In response, Mary gives a meandering response mentioning that Helena was not grown up when Mary knew her and that she “noticed her clothes more than her face” as “women do.”
Mary regains some composure and tries to fend off Poirot’s inquiry by appealing to her reputation as a governess. But her explanation for how she didn’t recognize Countess Andrenyi as Helena is less convincing. Mary, a self-possessed, intrepid young woman, even attempts to deprecate herself as vain to escape the truth.
When Poirot continues to press her, she’s overwhelmed with emotion and Arbuthnot yells at Poirot to leave her alone. Threatening to “break every bone in your damned body.” They both leave, but not before Arbuthnot insists that Mary has nothing to do with “this business.”
The dynamic of Arbuthnot as Mary’s protector is only heightened as Poirot inches closer to the truth. The man who before had wished for Mary that “you were out of all this” roars in defense of her, roused even to violence.
M. Bouc marvels at the “guess” that brought out Ms. Debenham’s former occupation. Poirot had already suspected Ms. Debenham’s position when questioning the Countess about her former governess. The Countess described someone the opposite of Ms. Debenham, and when she was forced to make up a name, she chooses Freebody. But Poirot recalls a shop in London called Debenham and Freebody, an association the Countess must have seized on.
M. Bouc is in a Watson role here as he praises the leap of logic that brought Poirot to Mary Debenham’s connection to the Armstrongs. Although Agatha Christie generally presents a “fair” mystery where the reader has the information needed to find the next twist, this is a rare case where information has been hidden. The existence of a shop called Debenham and Freebody was known only to Poirot.