Give me the central idea of chapter 7 "a long walk to water".

THe central idea is survival. Akeer is sick and needs medical attention even though the clinic is a few days walk away. Salva is overwhelmed by grief and fear. He clings to Uncle, looking around constantly. A lion took Marial in the night. He never would have walked off on his own, so the lion must have seen the small and weak boy and took him.