How does Bruno's mother react to her husband's job in The Boy in the Striped Pajamas?

When Bruno
comes home from school in chapter 1 and sees the family is packing up to move, he asks his
mother about it. She explains they have to move because of his father's job: it is very
important for his work that he take on the new assignment.

While Bruno's
mother acts brave and grows sharp with Bruno when he protests that he likes Berlin, her sadness
breaks through when he asks if they are moving more than a mile away. She responds as
follows:

"Oh my," said Mother with a laugh,
although it was a strange kind of laugh because she didn't look happy and turned away from Bruno
as if she didn't want him to see her face. "Yes, Bruno," she said. "It's more
than a mile away. Quite a lot more than that, in fact."

We can see that the mother is distressed by the new job that is causing them to have to
move, but she has no more choice in the matter than Bruno does. She is not aware at first of
what her husband's job at Auschwitz entails, but when she does later find out that he is
participating in exterminating Jews at the concentration camp, she gets very upset and angry at
him and returns to Berlin with her children.