After the failure of the latest Scientologist plot to overthrow the US government, the President has had enough. The Supreme Court rules that Scientology is no longer a religion, and is instead a threat to democracy. Across the USA, scientology centers are raided by crack police and federal government squads, in some places meeting with fanatical resistance.
A Scientologist center in any city. A building which could include an "auditing" center, dormitories, an assembly hall, a cafeteria, an armory, and a vault full of tax exempt riches. The building has been surrounded by the local police, the FBI, and the IRS. Inside the building are many Scientologists of varying levels of commitment. The die hard Scientologists will use the others as hostages.
Scientologists: Defend your sacred ground from the vile minions of the Macrab Confederacy! A Billion Years for L Ron Hubbard! These hollow shells the servants of Xenu call bodies are of no use to us, human life has no value. You have pistols, shotguns, rifles, and a good supply of illegal explosives.
Police: These whack jobs have crossed the line! Get in there, neutralize those psychos, rescue the hostages, and bring order to chaos! You have pistols, rifles, shot guns, and bullet proof vests.
FBI: Scientology is complete bull****, but people around the world believe in it. Obviously mind control is involved. Seize any documents you can get your hands on, papers, CDs, the whole shebang. Maybe we can find out how they spin horrible science fiction into holy books for thousands. You have assault rifles, pistols, rifles, snipers, shotguns, a helicopter, bullet proof vests, etc.
IRS: Now that it's not a religion, Scientology technically owes years of back taxes on it's billions of dollars in revenues. Get in there and grab as much money as you can. You don't give a damn about hostages. You are armed with pistols, rifles, shotguns, and various vehicles.
The Scientologists may kill hostages at will.
The Police and FBI should try to rescue as many hostages as possible.
The Police, FBI, and IRS are allied, although factional bickering is expected.