 According to Nathan Fillion , there was an episode in which the crew land on a dying planet . The inhabitants try to steal Serenity , after they explain to the crew about their need to get off the planet . The problem is that unless they were to run into another ship along the way , with the extra passengers , Serenity would not have enough fuel and oxygen to make it to the closest destination . While everyone else is asleep , Mal takes the ship himself and discovers that help never would have arrived . 
