Why does Livi choose to keep the knife she finds while cleaning rubble at Auschwitz in the book, Three Sisters: A Novel?

Livi keeps the small blade as an act of defiance and sovereignty in a death camp that seeks to obliterate her agency. She uses the knife to cut food so that she can share it with Cibi and Cibi uses it to slice the onion that helps Livi recuperate from typhus. Livi’s knife allows the sisters to physically survive and gives them the emotional feeling of freedom within the concentration camp.