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: 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: 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 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: Between the shots of Indy dressing as a Nazi and Captain Mohler reporting to Belloq and Dietrich, the Wurrfler appears to have advanced several inches forward (taking as reference the background behind the submarine, Mohler's location, and the fact that Belloq turns his head to the left to look at the Captain).
Continuity mistake: As Dietrich, Toht, Belloq and Marion board the Wurrfler, a naval officer descends the ladder and turns, his back to the ladder. In the next shot, he is facing the ladder.
Continuity mistake: The Angel of Death, judging from the position of the lid of the Ark (the two angels can be seen below the ghost), is located just above Dietrich's head. However, Toht screams as if it were right in front of him and Dietrich as if it were in front of Belloq (judging by their looks).
Continuity mistake: In the shot after Belloq's death, the generator and the rock Indy and Marion are on disappear.
Continuity mistake: As Dietrich and Gobler come into the tent, Toht's leather case can be seen already opened. In the next shot, the case is suddenly closed.
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: Eaton and Musgrove are sitting, waiting for Indy to open the book. When Indy opens it, suddenly Musgrove is standing. (00:19:43)
Continuity mistake: When Indy abruptly brakes the truck and the Ark box slides backwards, the poles on either side of the box disappear for the rest of the chase.
Continuity mistake: When Marion gets off the submarine, there are two soldiers behind her. In the next shot, one of the soldiers has disappeared.
Continuity mistake: When the Wurffler arrives to Geheimhaven dock, six soldiers and an officer are running towards the submarine. In the next shot, the seven men have disappeared.
Continuity mistake: On the blackboard, between the numbers 4 and 5, the word "and" is written. After the girl shows the "Love you", the word is replaced by a dot. (00:13:49)
Continuity mistake: Over Belloq's left shoulder and behind Toht, a soldier stands next to a klieg with a machine gun. In the next shot, the soldier's gun has disappeared. (01:44:25)
Continuity mistake: During the procession scene, in the shot before Toht takes off his hat, about twenty soldiers can be seen walking. After Indy leaves the procession and hides behind a box, in the next shot, there appear to be twice as many soldiers as in the first scene. Just before Indy shouts "Hello!", the quantity has returned to twenty.
Continuity mistake: When the two soldiers place the Ark on the altar, they move to the walls of the canyon, and Toht stands next to Belloq. A few shots later, the soldiers are next to the Ark's poles (where they will be in the next shot), and Toht seems to be very huge. (01:44:39)
Continuity mistake: As the Ark is placed on the altar, Toht moves to the left of Belloq. Behind the German, a soldier without cap can be seen filming with a hand-held camera. In the next shot, that soldier has moved to the opposite side of the canyon and is squatting. (01:44:24)
Answer: The scene you describe was indeed filmed. It was cut out of the US release of the film although I cannot speak for the Australian version. The scene also appears in the Marvel Comics adaptation. http://www.theraider.net/films/raiders/deleted_scenes.php has a list of this and the other deleted scenes.
Phil C.