One specific difference is how each character subjectively appropriates the world of "Out- With." Father believes that the move to Auschwitz enhances his career and makes him more important in the Nazi rank and file. Mother cannot overcome her fundamental belief that "what's going on" in Auschwitz is not good for her kids. While she wants to support her husband, her conflict in trying to be a good mother becomes evident. Gretel takes to Auschwitz because it coincides with her adolescent desire for assimilation and popularity. Nazism replaces dolls and this becomes the means by which she attains what she covets. Bruno cannot overcome his loneliness in Auschwitz until he meets Shmuel. It is this friendship that changes his view toward Auschwitz and one that inevitably seals his fate.
Another difference in attitude is how all of them end up leaving Auschwitz. Distressed at Bruno's absence, Mother takes Gretel back to Berlin, hoping against hope that Bruno has made it back there. Bruno, of course, dies in Auschwitz and father realizes that he had a role in perpetrating his son's death. At the end of the novel, he does not care what happens to him. From a point in which expectation and hope was synonymous with "Out- With," the reality of what hits the characters is Auschwitz's condition of being: Negation and death.