This discussion also involves how the island will blow up with Indy and Marion Ravenwood escaping. All of three of them quickly settle on having The Ark cause the explosion, since it would tie into the story even better. Along with something comical to sidetrack Indy when he rescues her.
In the finished film, he went to rescue Marion Ravenwood from Rene Belloq, who gave her this nice, fancy dress with a long skirt. One that she had to hold up in order to escape and go with Indy to discover the film’s major prize in the climax, The Ark of Covenant. A prize that is also the entire reason for the film.
One last discussion takes place between Kasdan and the story’s developer Phil Kaufman, who was set to write and direct The Adventures of Indiana Smith for Lucas in the 1970’s, before being hired to write the screenplay for The Outlaw Josey Wales. Also present for this discussion is researcher Deborah Fine.
They discuss Biblical matters as inspiration for the story which is already set in 1936. Kaufman also mentions he got the idea from his blood specialist, who wrote an article on The Ark of The Covenant back in 1955. It was about how Hitler searched for The Ark and use it as a way communicate with God like beings.