Each SWAT 4 scenario (mission) is randomly generated, with regards to enemy, civilian and hostage placements as well as their individual tendencies and aggression.
In a nod to the game's heritage in the original Sierra Police Quest adventure game series, the SWAT platoon commander is Sonny Bonds, the protagonist of Police Quest: In Pursuit of the Death Angel (1987), Police Quest II: The Vengeance (1988), and Police Quest III: The Kindred (1991).
In the mission "Victory Imports Auto Garage", there is an arcade game in the waiting room called "SWAT: Urban Justice". This is a company in-joke; Urban Justice was supposed to be Sierra/Vivendi's follow up to S.W.A.T.3 (1999), and they began advertising the game as "Coming Soon" in 2002 with a view to releasing later in the year. However, after a spending long time (to the order of years) in development purgatory, Urban Justice was canceled by Vivendi and never actually eventuated.
The game takes place in 2008.