Revealing mistake: The candles that adorn the wall in the Grail room do not appear to have a strong enough flame to put out the light they do that shines on the wall. In fact, it looks like there are electrical lamps just behind the candle. (01:49:20)
Visible crew/equipment: After Elsa gives Donavan the false Grail, he turns and you can see the reflection of the camera lens in the cup. (01:51:45)
Revealing mistake: When Donovan takes a drink from the false grail, he turns toward the camera and you can see the screw holding the base to the stem of the cup. (01:52:15)
Continuity mistake: In the temple in the Canyon of the Crescent Moon: After Harrison Ford cures Sean Connery by pouring water from the grail over him, Sean stands up with the grail in his hand. In the next shot, however, Alison Doody picks the grail up off the floor. (01:55:50)
Revealing mistake: Just as Elsa leaps from one side of the precipice to the other as the Temple collapses, a rock rolls from right to left and hits her right in the head before bouncing off. (01:56:35)
Continuity mistake: When Indy is trying to hold Elsa and keep her from falling and she's trying to reach the Grail, you can see her hand coming out of her glove. In the first shot of her hand coming out, it comes almost all the way out. In the next two shots, her hand is about halfway out, then it slips out and she falls. (01:57:00)
Visible crew/equipment: When Indy tries to reach the Grail his father convinces him to "Let it go" and Henry pulls his son to safety, then in the next wideshot of Indy, Henry, Sallah, and Marcus a crewmember wearing a short sleeved, white shirt and blue pants can be seen at the right side of the screen, just before it cuts to Henry's closeup. This crewmember can be seen again after the closeup of the knight. (01:57:45)
Continuity mistake: In the temple in the Canyon of the Crescent Moon, Indiana Jones rushes to his father's aid with the Holy Grail filled with water. He is shown pouring every last drop onto his father's wound by turning the Grail upside down, yet another camera angle shows his father clutching the grail to his chest, and there's still a bit of water in it.
Revealing mistake: During the "What happens at 11 o'clock?" joke, Jr. counts down ("12, 11, 10!" or something like that) with his hand, matte lines surround his hand to the point where it almost disappears.
Visible crew/equipment: When the lead bandit opens the magic cart door to find young Indy running away on the track, a crew member wearing a white shirt can be seen reflected on the door.
Continuity mistake: When Indy is stepping on the letters, he steps on the "O" and knocks the "P" loose. In the next shot, the "P" is intact.
Revealing mistake: Indy and Henry go through a tunnel to avoid the Nazi planes, but one flies into the tunnel anyway. When it goes into the tunnel, it's covered with matte lines, and it's the wrong color.
Factual error: When Indy is being chased by the tank there is a type 82 Kübelwagen - they weren't produced until 1940 and the movie is set in 1938.
Continuity mistake: In the motorcycle chase scene after the escape from Brunwald castle, Indy's hair is noticeably longer than it was in the castle scenes. It returns to the shorter length when they stop at the crossroads.
Continuity mistake: In the beginning of the boat chase two bullets hit the windscreen of Indy's boat. In the next shot the location of the holes has changed.
Continuity mistake: As Indy swings through the window to rescue his father, he gets hit on the head by a vase. His hat is all crumpled and tipped quite far back, then in the very next shot his hat is neat and level.
Factual error: During the motor boat chase through the canals of Venice, Dr. Schneider pilots the vessel between two ships, one identified as the John W. Mackay of London. Although the Mackay was commissioned in 1922, it was stationed at Halifax, Nova Scotia for service in the North Atlantic. It was deployed for the first time to the Mediterranean in 1942 - four years after the purported time of the movie.
Continuity mistake: When Indiana is showing Marcus the Grail Diary in his fathers home, he closes the book 4 times in a row without opening it - first 3 times inside the room, and then once on exit.
Other mistake: When Marcus is knocked out at the library, look at his legs when he is dragged away - they are purposely crossed in a way which couldn't have happened naturally for a body being dragged - the actor did it to keep himself comfortable.
Continuity mistake: When Indy and Elsa escape underwater, and surface from the tunnel, Indy's suit should be drenched, but it only has water stains. Then during the speedboat chase, their clothes are completely dry.
Chosen answer: They're not, no. An individual doesn't become immortal after one drink - it requires them to drink regularly in order to remain alive. So neither Jones has been rendered immortal, merely healed of any wounds that they might have. But your surmise is basically correct - as the Grail cannot leave the shrine, any individual wishing to use it to prolong their life must stay there if they wish to enjoy its effects.
Tailkinker ★
Also, in Indiana Jones and the Kingdom of Crystal Skull, Henry Jones, Sr has passed away before the start of the story and therefore was not immortal.
raywest ★