Poirot, M. Bouc and the doctor sit in the dining car and review the gathered evidence. Poirot is most intrigued by the case because he is cut off from all normal detective or police procedures and must use his intellect to solve the case. M. Bouc and the doctor are not convinced. Poirot first draws the men's attention to Hector McQueen, who repeatedly told Poirot that Ratchett spoke no French. Thus, the voice from Ratchett's compartment at 12:47 was not Ratchett, but someone who spoke French. Poirot also points out that the only time someone could have entered Ratchett's compartment was when the train stopped at Vincovci, when the conductors got off the train. Otherwise, the conductor left his post only between 1 a.m. and 1:15 a.m. Poirot make a list of the passengers, their possible motives for murder and given alibi.
Poirot identifies the following questions: who owned the handkerchief found in Ratchett's compartment; who dropped the pipe cleaner; and who wore the scarlet Kimono; who wore the Wagon Lit uniform; what is the significance of the Ratchett's watch stopped at 1:15; what time was the murder; and how many murders there were.
Poirot deduces the handkerchief was probably dropped, but the pip-cleaner was left as a faked clue. M. Bouc struggles to figure out the rest of the questions, but finds himself quite lost and is especially confused about the watch. Poirot points out that he had all the passengers write out their names. Everyone took the pen with their right hand except for Princess Dragomiroff, who did not write—a possible answer to Ratchett's wounds inflicted in both a right- handed and left-handed manner. The doctor is certain there must have been multiple murderers because of the way the blows were struck—in different directions, at different times, with varying force.
After fifteen minutes, the men finally speak. Both M. Bouc and Dr. Constantine are quite lost in the matter, but Poirot's seems to have some ideas. Poirot points out important clues: "a remark made by M. Bouc...we were surrounded by people of all classes, of all nationalities...somewhat rare at this time of year...the position of Mrs. Hubbard's sponge-bag, the name of Mrs. Armstrong's mother, the detective methods of M. Hardman, the suggestion of M. McQueen that Ratchett himself destroyed the charred note we found, Princess Dragomiroff's Christian name, and a grease spot on a Hungarian passport." Poirot believes Countess Andrenyi's real name is Helena Goldenberg, daughter of Linda Arden and sister of Mrs. Armstrong. Despite McQueen's indication, the note was purposely destroyed to erase all evidence of an Armstrong connection and thus, the murderer was intimately connected with the Armstrong family. Countess Andrenyi purposefully spilled grease on her passport to obscure her Christian name and possible suspicion and the Princess Dragomiroff lied about knowing Helena's whereabouts.
A detective who is too morally and intellectually superior can alienate the reader. The Watson character, the sidekick used in many mystery novels exists to counter this effect. Watson is comedic and certainly not as intelligent as Sherlock Holmes. He not only acts as the reader's surrogate, allowing him to be privy to all of Sherlock Holmes' movements, but also is a character the reader can feel superior to. The "Watson," typically a gullible, dim-witted and morally upright character, seems much less intelligent than Holmes. We immediately feels closer to Holmes because we assumes that we are more intelligent than Watson, even if we cannot solve the crime. We do not identify with Watson, but we are amused by him. In Murder on The Orient Express, the "Watson" is M. Bouc and Dr. Constantine. As exemplified in the beginning of Part three, they are comedic characters that are obviously less intelligent than Poirot.
In the beginning of Chapter 1, both M. Bouc and Dr. Constantine are thoroughly frustrated. When Poirot enters the dining car he is clearly emotionally removed from the two anxious men, "he took out his cigarette case and lit one of his tiny cigarettes. His eyes were dreamy." Poirot clearly enjoys working on the case and takes great pleasure in the challenge of the non-traditional case. Poirot tells the men that they have the evidence of their eyes and ears and now need to use their intellect to crack the case. The intellectual challenge is not something that M. Bouc looks forward to. M. Bouc's reluctance may not be without reason, it always takes him awhile to understand ideas brought forth by Poirot. By Chapter 2, the men have all but given up their attempts to figure anything out. They have essentially left the case solving to Poirot. The reader can literally hear these thoughts in Chapter 3. When the men are all told to close their "eyes and think," M. Bouc and the doctor have difficulty. The thoughts of the two men are comedic: M. Bouc thinks for awhile about the unapproachable and cold nature of English men and women, Dr.Constantine's mediation wanders into pornographic thoughts of a woman named Zia. When the "thinking" time is over, M. Bouc and Dr. Constantine tell Poirot that they have "reflected with great earnestness," but neither had found any success. Dr. Constantine, thinking of Zia notes, "I have thought of many possible theories, but not one really satisfies me."