Audio problem: When Natasha is tied in a chair and she fights her way out. When she reaches the third man and "head butts" him, her head is several centimeters away from his and her hair is the only thing that touches him, but we still hear the sound of a hard impact. (00:14:25)
Audio problem: When Bruce Banner meets Natasha Romanoff for the first time in Calcutta, there's a shot from behind her where Natasha is heard talking but her reflection in the small mirror behind Bruce isn't. (00:17:45)
Audio problem: In the scene where Black Widow is hanging off the back of the flying Chitauri chariot, one of the Chitauri fires his gun, but there is no sound effect to go along with the blast as there is with the other blasts. (01:51:50)
Audio problem: When one of the computer operators resumed playing Galaga, the sound effect heard is for an enemy ship attempting to capture the player's ship, but what's shown on screen is normal gameplay.
Answer: People have been smuggled in and out of countries for decades, grease the right palms and talk to certain people, if you don't get in under the radar, phony papers could.