A level early on in the game, which is the catalyst to the rest of the story line, where an undercover CIA agent joins a group of Russian ultranationalist terrorists to engage in killing innocent civilians at Sheremetyevo International Airport in Moscow (renamed Zakhaev International Airport, after the prequel Call of Duty 4's antagonist).
You don't need to kill anyone to successfully complete it and at the end, you get killed after being found out that you're an American secret agent. Whilst you lie in cold blood and the Russians escape, the authorities find you which causes mass conflict on both sides of the Pacific.
In certain territories, this level is modified so that killing anyone results in instant mission failure or it has been removed completely. The level can be skipped at no penalty and no reward will be gained from successfully completing it.
Guy #2: I thought the departure boards flicking to delayed was awesome.