Examine situations in the novel where characters have acted against their own principles. Do you believe the rules change when survival is at stake, or should people stick unflinchingly to their sense of right and wrong?

I think the rules certainly change when survival is at stake. Certainly Hans wanted nothing to do with the Nazi party but knew he had to join to keep his family safe. Principles are largely for people that have nothing to lose. When survival of one's own life or, more importantly, one's family is in peril, principles are not so defined.