We're getting there. They are the ones who gave you that procedure, after all. Just because your traincar is saner compared to the others does not mean other people haven't tried offing themselves and failed. If anything, the worn-out flesh and bone made it easier for the pair to morph you all into one ginormous being.

How it looks like, however? I'll leave that up to your imagination.

3,437 days in. By this point, you already know how things work. Take care of the suicidals, hold the fort that is the traincar, get frequent checkups from the doctor and nurse. By this point, the traincar has become a little city of its own, dubbed... Lovely Town. You and the other passengers are happy and satisfied, having forgotten your own lives outside the train.

724,284 days in. You're minding your business, molding what's left of the carcasses into square molds that'll help bolster the defenses of your little town. Then... the train cars finally open, and uniformed people immediately come in and take everything down. They use tranquilizers to take you and the others down, but before the uniforms have taken you in... You realize that the doctor and nurse have vanished.

Either way, you've finally reached your destination! Turns out that ten seconds already did pass -- outside the train, that is.

[ see? it's a good ending! ]