As Ender enters the shuttle, he immediately notices that its built to function with an up and a down. How is this indirect characterization of Ender?

The author plays with the idea of human manipulation throughout the novel: when the ends involve saving the human race, are there any means that are off limits? In this case, Ender at least is intelligent enough to understand that he is being manipulated and can choose whether or not to keep participating in his own breaking down and building up.