For anyone who attended operation silent night in memphis, that warehouse would be ideal for this scenario.
A terrorist group has been monitored by the FBI for several months. recently, activity in a warehouse rented by one of the terrorists has increased. Vans and dozens of men have been seen entering the building in the past few days, some wearing NBC suits and radiation protection. The feds have reason to believe this group has somehow smuggled some sort of nuclear weapon onto U.S. soil and has surrounded the facility. The terrorists are heavily armed. FBI(or any U.S. group, could be navy seals for that matter) are getting ready to storm the building and locate the weapon before it can be assembled. U.S. team has one hour or some set time limit to locate the bomb. Once the weapon is located, NEST teams will be called forward and the U.S. team has to hold off the area for 5 minutes, then finish off the rest of the terrorists, but disabling the bomb is the primary objective. Booby traps and mines can be used, as can flashbangs if they don't produce smoke. Flashlights would be a must.
To make it interesting the terrorists could use hostages, and could surrender then try to overtake their captors. Anything could go within safe and reasonable limits.