I'm sorry you were triggered. :( This community as a whole should probably be better at using tags as warnings for other users.
I also thought the references were wholly unnecessary. I thought the Japanese culture was generally more respectful towards the deceased so it threw me for a curve. It could have been a poor translation from text that was initially more reverent. Or it could have been an attempt at dark humor coming from the honmae/tatemae perspective, though if that's the case I think it missed its mark. But regardless, there were a multitude of other ways to show frustration or overwhelm with his job that would have fit better within the more lighthearted tone of the story.
IMO, it's to show how worst can a train conductor's day can be and to contrast it with the effects of seeing the student. Even if the conductor in the story he has experienced such thing, his stress would be over once he sees the kid.
why artist decided to add "tuna" and suicide references? its not even funny just extra and im so triggered as a suicidal person.