Complex sentence: Lee finds the nerve to burst into a house where several villagers are held captive, shooting the bandits guarding them, allowing the villagers to join the fight, but is then gunned down as he leaves the house.
Split into simpler sentences: Lee finds the nerve to burst into a house where several villagers are held captive, shooting the bandits guarding them, allowing the villagers to join the fight. Lee is then gunned down as he leaves the house.