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

Q: 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?

A: Why does Margot Robbie wash Chiwetel Ejiofor in Z for Zachariah?
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Q: Near the start of Guardians Of The Galaxy, Rocket says about the Xandarians:    Xandarians. What a bunch of losers. All of them in a big hurry to get from something stupid, to nothing at all. Pathetic.   What does he mean by this?

A: Why are Xandarians in a hurry to get to nothing at all?
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Q: What was the reason behind the conversion of human into USB in the movie Lucy?   Why did the heroine change herself into USB when she used 100% of her mind, and then texted the policeman ("I am everywhere")?   She traverses many old eras, and in the end just forms a strange structure, giving the researcher (scientist) USB and then that huge structure falls off?

A:
Why did Lucy convert herself into a USB?
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