Factual error: When Tom Cruise chases the villain in a parking lot in Mumbai, the "Parking" sign is written in Kannada (the scene was shot in the Sun Network station at Bangalore). Regional signs in Mumbai are in Hindi or Marathi (the state language of Maharashtra, of which Mumbai is the capital).
Factual error: The cars in the car park scene are left hand drive (specially the ones involving the main action scenes), but the sequence is set in India, where the cars are right hand drive.
Factual error: Ethan Hunt's iPhone in Dubai is connected to the AT&T network in Dubai, when that network doesn't operate in the UAE.
Factual error: There are no areas with palm trees, Arabic market stalls etc. anywhere near Burj Khalifa. It lies in the middle of a newly developed, very polished business area.
Factual error: In the scene where Tom Cruise enters the server room and plugs his thumb drive into the server, it is a Dell power edge 2650 which was released around 5/6/2002 and stopped shipping around 8/13/2004. The building was opened in 2009 - it's beyond belief an ultra modern building would be run using a cluster of out of date, out of warranty, underpowered computers.
Factual error: When Ethan runs after the villain after coming out of Burj Khalifa he reaches DIFC, which is not a walkable distance from the tower, and you can see Burj next to the DIFC Gate which isn't there in reality.
Factual error: In the scene with the cars in elevators, right after Ethan jumps into a car to get the briefcase, he sees the bad guy coming down on him in the mirror, yet this is an impossible angle and there's no way he could have seen that.
Factual error: After the IMF crew rescue Ethan Hunt from the Russian prison, they stop and Ethan Hunt walks up to a payphone. The information on the telephone is in Russian, but worded incorrectly.
Factual error: When the four main characters get together at the end of the movie and meet Luther, it is said to be in Seattle. Benji says all the people around them were almost vaporized. The nuke landed in San Francisco and if it had detonated, it wouldn't have affected Seattle so drastically.
Answer: He considers Hunt to be a friend, so did what he asked. In addition, by carrying out the deal he has ingratiated himself with Sidorov as well.