The film Snowpiercer largely follows a man named Curtis as he moves toward redemption, through securing a better life for the oppressed people in his home, the tail section of the train. However, throughout the film, Curtis is constantly being forced to choose whether to push forward (camera right) or fall back (camera left) and in doing so, Curtis must make moral choices about what he is willing to sacrifice. Should he push forward through the car full of ax-men in an attempt to capture Minister Mason, or should he fall back and attempt to save Edgar? Should he move forward through the school car with his prisoner or return to execute her? Should he ascend to maintain the engine or move back and climb down to rescue Timmy?
Each choice that Curtis makes shapes his moral code and shows him, more than anything else, to be a utilitarian hero, willing to use and discard people in order to secure his intended goals. In many ways, it is from this ability to divorce emotion from decision making that caused Wilford to tap him for command of the train. Curtis may be a man of the people, but he is not above feeding dozens of people into the meat grinder if it moves him closer to his goals. With each step forward, Curtis puts more of the train behind him, to the point where when he is standing in the engine and observes the battle taking place in the train car behind him, the very humans he originally set out to save appear monstrous, dirty and unworthy of his salvation. It is not until one of these people that Curtis has now condemned shows him Timmy, a symbol of the purity that Curtis set out to preserve, that he is brought back to a state of mind that supports saving the innocent. In many ways, his sudden aversion to inflicting violence on others is what destabilizes the closed ecosystem of the train, but is the ultimate fate of the train due to an even simpler change than one occurring within Curtis’s mind? Is the destruction of the train purely a result of Curtis stopping his progression forward?