Given scene/plot descriptions from movies or TV shows, and given a specific question about the scene, summarize the question into a title

I haven't finished Z for Zachariah yet, but is there radiation in the water and an intense scrubbing will protect you from it? Why does Margot Robbie wash Chiwetel Ejiofor in Z for Zachariah?
Why does Margot Robbie wash Chiwetel Ejiofor in Z for Zachariah?