Poirot admits to M. Bouc and Constantine that he was testing Miss Debenham, and was looking for a flaw. He doesn't think she would have committed a crime of passion, so he insists that they start thinking about the death as totally planned out beforehand.
Poirot explains that he suspects Mary because of the conversation he overheard at the train stop in Konya. He thinks she's totally capable of having planned the crime, being cool and resourceful and all.
The lady's maid, Hildegarde Schmidt, is next. Poirot is super sweet and kind to her. (Again, strategy.)
Hildegarde confirms that she went in to Princess Dragomiroff's room last night to give her a massage.
Hildegarde does not have a scarlet dressing gown.
Before turning in, she went to fetch a rug from her compartment. She saw no one but the conductor, who was coming out of one of the middle compartments. She had not seen him before.
Hildegarde has not been to America, but she has heard of the Armstrong case. The handkerchief isn't hers, but she hesitates when Poirot asks if she knows whom it belongs to. She says she doesn't.
The three conductors, including Pierre Michel, are called in. She says the conductor she saw is not in the lineup. That man was small, dark, and had a mustache and a womanish voice. (Sound familiar?)