Continuity mistake: Throughout the film, Tony Stark's chest ring can be seen glowing through his shirt except for two occasions when it's suddenly off - after Loki escapes from the helicarrier, and when Loki and Tony Stark are talking in Stark tower, even when he's wearing the same shirt. (01:35:30)
Steve Rogers: Is everything a joke to you?
Tony Stark: Funny things are.
Trivia: When Loki is grabbed by the Hulk and repeatedly smashed into the floor, Tom Hiddleston had a rope tied around his ankle which was pulled to achieve the effect. Although, Tom was told that the rope would be pulled while speaking to the Hulk, he was never told when the rope would be pulled so his reaction to quickly be pulled down was real.
Question: How would Bruce be able to get Calcutta? He's made it a habit of never using anything that could be used to track him, so going anywhere, even to another country, would seem impossible.
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.