Complex sentence: Suddenly, the boulder crashes through the doorway where it was stuck and flattens René Belloq and the Hovitos, as Indy jumps away into Jock's seaplane, where Indy is seen with a check list and crosses "Idol" off the list.
Split into simpler sentences: Suddenly, the boulder crashes through the doorway where it was stuck and flattens René Belloq and the Hovitos, as Indy jumps away. In Jock's seaplane, Indy is seen with a check list and crosses "Idol" off the list.