Continuity mistake: When Indy throws Terry Leonard out of the truck, the forest they were driving through disappears. Then Indy closes the truck's door and the forest reappears. (01:24:22)
Continuity mistake: In Geheimhaven, Indy watches the submarine hidden behind some ropes. When Marion comes out of the submarine and the camera focuses on the back of Indy's head, the ropes disappear. (01:39:13)
Continuity mistake: As the sergeant climbs to the truck's roof, Belloq turns his head to watch the scene. In that shot, the staff car is passing next to a group of plants. In the next shot, almost all the plants have disappeared. (01:26:55)
Continuity mistake: When Indy runs over the sergeant, the background behind the truck changes between shots, going from the desert to a mountain. (01:28:45)
Continuity mistake: Dietrich and Gobler walk forward to stand next to Belloq while he's saying, "Once again, Jones..." In the next shot, Gobler has disappeared (this can be spotted by the distance between Belloq and Gobler's foot in the first shot). (01:10:57)
Continuity mistake: As Gobler's jeep is returning to the road after being hit by Indy, Gobler's goggles move from his eyes to his cap between shots.
Continuity mistake: At the beginning of the Truck Chase, when Billy Horrigan starts shooting at Indy, Reg Harding's right hand goes from grabbing the front passenger seat to grabbing the metal bar of the jeep between shots. (01:23:28)
Continuity mistake: In the canyon, in the shot of Toht, just before Belloq says "Do as you will", everyone in the background (Marion and her two guards, Dietrich, some soldiers) is gone (taking as reference the giant stone behind Belloq and the characters' positions in the previous and next shots). (01:43:49)
Continuity mistake: Dietrich asks, "If we refuse?" Next to him stand four soldiers in a row, looking at Indy. In the next shot, the soldier who was holding a rifle is gone, and the two with machine guns are now giving their backs to Dietrich. (01:42:52)
Continuity mistake: When Dietrich and Toht look at the ghosts that pass behind them, the column of mist that is coming out of the Ark disappears.
Continuity mistake: When Indy is entering Marhala Bar, Steve Hanson is right behind him, following Indy inside. In the next shot, Steve is suddenly standing next to Belloq (he seems to have arrived before Indy did). (00:43:08)
Continuity mistake: In the Bantu Wind, the right arm of the soldier standing next to where Indy is hiding changes its position twice during Katanga's and Dietrich's speech. (01:36:18)
Continuity mistake: As Dietrich and Gobler come into Belloq's tent, Toht's leather case can be seen already opened. In the next shot, the case is suddenly closed.
Continuity mistake: While the Holy Fire is killing the soldiers, in a shot of two soldiers being hit by the light, the stone wall is missing in the background of the scene. (01:47:30)
Continuity mistake: When Marion arrives on the deck of the Bantu Wind, Dietrich turns to look at her. Katanga is in the background, behind the colonel. But, just before Marion hits Dietrich, Katanga appears on the opposite side from where he was and catches Marion. (01:36:00)
Continuity mistake: When the gunfight at The Raven begins, the Ratty Nepalese crawls next to two tables (one of them has the medallion and the log). He knocks down the one without the medallion, but in the next shot, the knocked down is the one that has the log and the medallion. (00:31:10)
Continuity mistake: During the procession, after Indy hides behind the box, Captain Mohler and Arnold Toht can be seen walking behind the Ark and on the Ark's right, respectively. In the next shot, Mohler is walking in front of the Ark and Toht, on the Ark's left.
Continuity mistake: In the first scene of the procession, the Nazis are walking in a straight line along a path. In the next shot, they are now going around a curve.
Continuity mistake: After the kliegs behind Dietrich, Belloq, and Toht explode, the Ark's energy begins to destroy the soldiers' guns and the kliegs next to them. In some shots, the kliegs on the altar are still working.
Continuity mistake: Just before Belloq says "It's beautiful!", there is a black machine (which is not the German camera or the generator) in the bottom middle of the screen, just below the approaching ghost. It is also visible when the Angel of Death is revealed. This machine disappears when the Ark begins to kill the soldiers.
Answer: Indy and Marcus Brody believed that the Ark needed to be studied. They certainly didn't want to put it back where it was found. They believed that the U.S. government would find the best archaeologists, researchers, and scientists in the world to study the Ark. They are both upset that instead, the government has decided to simply lock the Ark away. This is why Indy says, "Fools. They don't know what they've got there," as he is leaving the building.
BaconIsMyBFF