Visible crew/equipment: At the end of the film, when the news about the train and helicopter accident plays on the TV, as the camera pulls out, the camera's reflection is visible in the blue window shutter. (01:44:08)
Factual error: When the helicopter blows up, the train stops dead in its tracks almost instantly. A high-speed train like the TGV needs more then two miles to come to a complete stop from its top speed, or at least from the speed it's traveling at. And a Little Bird attached to it wouldn't make the slightest bit of difference.
Jim Phelps: Of course he knew. Just when he knew is something of a mystery. You mind telling me, Ethan? Was it before or after I showed up in London?
Ethan Hunt: Before London. But after you took the Bible from the Drake Hotel in Chicago.
Jim Phelps: They stamped it, didn't they? Those damn Gideons.
Question: Did Ethan actually know it was a mole hunt to trap Jim, or was he oblivious until he worked it out at the train station?
Answer: Ethan never thought it was a mole hunt to trap Jim. He found out from Kittridge at the restaurant that it was a mole hunt, but Kittridge believes that Ethan is the mole (the money his parents mysteriously receive). At the station Ethan realises that Jim must be the mole since it is too convenient both he and his wife survived. However, the hunt to catch the mole was never directed at Jim - Kittridge never suspected him until at the end when he sees Jim alive.
swordfish
Actually had suspicions before Jim showed up. Ethan found the Bible that was stamped from the Drake Hotel. Where Jim had literally just come back from before the mission. It made no sense otherwise why that would be in Jim's possession.