The Mysterious Major

What did Schmahling mean when he said that in crushing the boy in his classroom, he was destroying something in himself? What was he destroying? How was it like what the Nazis were destroying in the people they ruled?

In this story, a major in the army is a protector of Jews, but he only helped anonymously. He sent anonymous phone calls warning Jews of raids, and so on. He was a teacher before he was in the army, and one day the Major was telling about beasts, and he was talking about the lion when the class dunce interrupted him. The class dunce interrupted him by saying that he had seen a rabbit yesterday. The teacher was angry because, obviously he did not like to be interrupted by the class dunce, who was not even talking about beasts, but about a rabbit. The teacher got very angry at the boy and called him a lot of unpleasant names and told him to shut up. The boy did not talk again for the whole year (in class). Later on, Schmahling looked back on this moment and was very ashamed of himself, and he said he had destroyed this young boys moment of happiness. He said that when he crushed the boy in the classroom, he was destroying something in himself. I think that what he meant was that, in ruining a boys moment of happiness, he was destroying a piece of his heart by being hurtful, and watching the boys happiness fade because of him. He was destroying the boys happiness, making him feel small and powerless, while the teacher told him what to do, similar to how the Nazi's made life for the Jewish people miserable, and making other civilians feeling like they needed a leader, and that they were powerless, and small, but with the help of the Nazi's they could be powerful and big, so they had to help.