Factual error: When the bus slams into Brian's car at the start, Brian's car doesn't move an inch. Given the speed and weight of the bus, Brian's car should have been shunted a good distance. (00:01:45)
Factual error: At the end we see Loco and Santos in casinos in Monte Carlo. However the roulette wheel has a 00 and a 0 on it (Green slots). The double zero tables are never found in Monte Carlo. (01:54:00)
Factual error: Given the specs given in the movie (7x12 feet) and assuming standard container height (2.389m) and 45cm thick walls, the vault would weigh at least 73.76 tonnes. Not 10 tonnes.
Answer: Hobbs doesn't see that scene, though he probably does guess part of what happened - ie. that they swapped the vaults. The scene is played as a reveal for us, the audience, to show us how the vault that is supposed to be full of money is now suddenly empty.
roboc