Directed by: John Woo
Starring: Tom Cruise, Ving Rhames, Brendan Gleeson, Thandie Newton, Dougray Scott, Richard Roxburgh, John Polson
Other mistake: Ambrose smacks a stone on Ethan's forehead. No blood nor even a bruise appears seconds later when Ethan is kicked in the face and we get a close-up of him.
Other mistake: Luther tells Ethan that he will only have 40 seconds for the louvres to remain open for him enter the ventilation shaft at Biocyte before the alarm goes off. But the warning message on Luther's computer says that the limit is 20 seconds. (01:06:30 - 01:09:10)
Factual error: In the scene at the race track where they show the virus infecting and destroying cells in the blood stream, they clearly show that it is red blood cells being infected. Viruses, in order to replicate, require the cell's DNA replication machinery. However, mature red blood cells in the circulation no longer possess this machinery since they no longer have a nucleus or DNA. It would therefore be impossible for this virus to replicate.
Ethan Hunt: You turned around.
Nyah Nordoff-Hall: What are you going to do? Spank me?
Trivia: The delays on the MI:2 shoot cost two of the actors high profile roles: Dougray Scott was replaced by Hugh Jackman in X-Men, and Thandie Newton was set to play Lucy Liu's role in Charlie's Angels, but this shoot ran so long that she didn't want to commit to another 6 month shoot immediately, so pulled out.
Question: How did Ethan Hunt know he was going to switch places with Hugh at the end of the film requiring him to take two masks with him to swap different faces?
Answer: The only thing I can think is because they're in Sean Ambrose's hideout, and he's an ex-IMF operative, then he possibly had the gear required in there. Ethan found it before the encounter with Hugh, and it's simply not shown. Other than that, it's an error.