What makes some overcome evil, while others are coopted and destroyed?

In Keep Saying Their Names, Simon Stranger tries to postpone the second death of Hirsch Komissar, his great-grandfather-in-law, a Norwegian Jew murdered by the Gestapo in 1942. https://www.jpost.com/israel-news/culture/what-makes-some-overcome-evil-while-others-are-coopted-and-destroyed-634417