Conan remembers the Vodka lookalike saying "I can finally have a smoke". Conan realizes this must be because the transaction the men in black had with the person in the dining car cannot stand the smell of smoke. Therefore the person with the bomb must be in a non-smoking car of the train. According to Mitsuhiko there are eight non-smoking cars on the bullet train.
The Gin lookalike made a remark about how the person with the bomb is probably "looking out at the last scenic view" they will ever see. Conan and the Detective Boys realize the person with the briefcase must be in one of the two-story Green Cars. Mitsuhiko explains only one of the three Green Cars is non-smoking.
Conan notes that the man in glasses with the laptop is trading stocks and has a gold Rolex watch. Conan remarks the man must really be raking in money. The man in glasses shouts at Conan that he could not possibly go anywhere on the train due to the amount of work he has.
The woman in the Green Car has a cell phone and remarks to Conan that since the sky is clear today "you can see Mt. Fuji" from her window. The woman claims to have not visited the dining car during the trip.
The elderly man does not seem to hear Conan's question correctly, so Conan is unclear whether the man did or did not visit the dining car.
Although the brutish man with gold rimmed glasses doesn't answer Conan's question outright, it's clear the man visited the dining car because he wipes his glasses with one of the dining car napkins.
When the Vodka lookalike questions his partner about the bomb being timed, the Gin lookalike replies that although the bomb isn't on a timer, the bomb will definitely go off when the person with the briefcase unknowingly triggers the detonation button. Conan realizes this means the explosion will be set off by the passenger's "reaction to something".
After ruling out the brutish man Conan knows went to the dining car (the briefcase was full of underwear), Conan realizes one of the passengers he spoke to said something strange.
The woman claims to have had a great view of Mt. Fuji earlier in the train ride, but it would be impossible to see Mt. Fuji from her window in the Green Car. She must have been in the dining car at the time and mistook her view from the dining car for the one back in her Green Car seat.
The woman lied about going to the dining car in order to cover up the transaction she had with the men in black.
Conan also realizes that the detonation button the Gin lookalike referred to is when the woman dials a specific telephone number on her cell phone.
The woman manages to dial the number on her cell phone at 3:10 PM, but thankfully Conan manages to use the Power-Enhancing Kick Shoes to kick the briefcase out of the train just before it exploded.
The woman's motive for making a deal with the men in black was to gain "inside information on the trading market" in exchange for 100 million yen.
The men in black's motive for planting the bomb of course was to kill off the woman and cover their tracks while getting away with a hefty amount of money.
