How does hannahs background knowledge of the holocaust influence chayas behavior?

Chaya knows what Hannah knows. I guess hindsight is 20/20 but really there was little that she could do to change anything. Although she knew what was happening and its eventual outcome, she was as powerless as the other prisoners. Hannah does warn the others about the extent of the genocide. She repeats that six million of them will die. Her friends and family just think she is batty from her sickness. In the end, Hannah's knowledge only helps her to be a little more reflective about her horrid experience.