Continuity mistake: When Ethan gets instructions on the screen in the payphone there is a countdown on a screen visible, a split second later when the camera shows the phone from a distance that screen has gone and the payphone is 'closed' again. (00:19:10)
Continuity mistake: When Cobalt piggybacks IMF's frequency, he says "Team leader, awaiting your go sign. Standing by to detonate." When Sidorov plays the recording back to Ethan in the hospital, the order has changed to "Awaiting your go sign, team leader. Standing by to detonate." (00:31:25)
Continuity mistake: When Ethan wakes up in the hospital he realises he's handcuffed to the bed. In the closeup of his right hand, the handcuff is around his wrist with its single metal bar facing out and the double bar facing Ethan, but when the nurse moves his gurney the handcuff is around his right wrist the opposite way, with the double bars facing out. Quite impossible for this to occur. (00:31:50)
Continuity mistake: As Ian chases the bad guy and the sandstorm approaches, he enters a covered area just as the shadow of the storm (moving much faster than he is) reaches him. When he exits the covered area, 5 seconds later, the shadow remains *just* overtaking him, while it should be easily 10 meters past him by then. (01:16:43)
Continuity mistake: After the sandstorm ends, there's a shot showing Ethan's back and the sand moves away. Ethan's shadow is behind him, meaning that the sun is in front of him, butwhen the shot changes to view his front, the shadow is in front of him, meaning that the sun is now behind him. (01:22:05)
Continuity mistake: Ethan is walking down the steps of the airplane and the car drives by. He is then one step back up. (01:31:15)
Continuity mistake: Early in the film, Ethan is talking with Jane in the back of the van after they have dropped off the Russian. There is a silver flexible arm lamp hanging down that is visible when the camera is on Jane, when the camera cuts to Ethan and back to Jane it is no longer visible. A few camera shots later and it has reappeared in the original location.
Continuity mistake: During the sandstorm, when Ethan is run over by the car, its left side mirror breaks, but appears fixed in the brief opposite angle.
Continuity mistake: When Ethan drives the BMW off the parking lot in Mumbai we see that his face is covered in blood. After he disarms the ICBM and the Russians comes in to arrest him we see that his face is clean.
Continuity mistake: The mess around dead Hendricks (glasses, position of suitcase) changes between shots.
Continuity mistake: As Ethan and Benji go through the Kremlin Benji isn't wearing glasses, but a cut later he's wearing them.
Continuity mistake: When Ethan is hanging on the outside of the Burj trying to kick in the laser-etched circle of glass, his hand position changes from outside the circle to across the line of the circle as the shot changes from outside to inside the building.
Continuity mistake: When Moreau is brought to the room and sat on the chair, her hair swaps from messy to brushed between shots.
Continuity mistake: When Ethan is climbing Burj Khalifa, the sandstorm is approaching from the north. When he exits the building he runs to the north, and the sandstorm is now approaching from the south.
Continuity mistake: When Ethan disguised as a Russian officer passes the security scan at the Kremlin, he goes without the controller giving him back his fake ID card. In the next shot showing him, Ethan puts it back in his pocket.
Continuity mistake: This is at the fancy car park in India. Hendrick has just jumped off the platform. The briefcase as well as his body move in subsequent shots. Note the lines in the concrete floor.
Continuity mistake: In the prison break scene, when Benji opens the second prison cell, the computer shows that he is opening the second cell, but the third cell actually opens.
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.