Wilfrod still had power over him and was alive. Symbolically yes, but then again the raging crowd was coming after them, it required rash action.Humanity turned against itself, once the lower class stormed to kill Wilfrod and once Curtis reaches power the higher class storms to kill him. It's a never ending struggle that can symbolically represent things from political parties to capitalism v communism when one side gains power the other lashes back and the conflict continues with the inequality and corruption.The only way to end the inequality and corruption was to henceforth end the human race and make it start anew. With a new start there is now hope for life on Earth to continue and for human survival. (Basically the message is, the train humanity is on board sucks but to truly be able to fix the problems, such as the rich depending on the poor to be poor to be rich, you'd have to destroy the train and that means most of humanity itself.)