This is not my original work. See previous.
Lastly, let us examine Inami’s relationship with Kazuta Haruka. Why does she think that Koharu will be able to understand her relationship with Kazuta Haruka? Why does she think that Koharu will understand herself? If we go back to her id well, we can pretty much guess that Kazuta was also on the train that killed Inami’s mother. This would have caused them to have a feeling of guilt, making them feel like killers. All of the people in the train are dead except for the two of them, showing that even though she sees the train as the killer, all of the other passengers should be punished. This sort of childhood experience would make it more reasonable for the two of them to become serial killers. After Kazuta was killed, who else would be able to understand her? Because there would be nobody else to understand her, meaning that there was no more meaning to her actions, she pleaded guilty and was taken into captivity. Her wish for someone to keep living eventually turned her and the person most important to her into serial killers. Inami hoped that there would be someone else to understand her, and this made Momoki feel sympathetic of her, hoping that her world would last longer and allowing Sakaido to stay. The train made Sakaido/Narihisago Akihito wonder why he wanted to find the reason of Kaeru’s death, why he would have to keep surviving in the id wells. In this world, everyone felt pain. However, tragedies are still tragedies, and the two remaining people on this train could only stare out of their windows, burdened with guilt, wishing to move closer to one another yet unable to do so. Only they know that they will always be together, even though they sit far away from each other. But the eternal railway helped them understand each other, and that would be enough.