I've serviced fire alarms in big cinemas like that. The protocol is pretty complex. Once smoke is detected anywhere in the building *all* of the projectors shut down, the RTU's are shut off, house lights come on full brightness, emergency exit signs flash, elevators recall & lock open, and a coded message - "the siren tone" with voice egress directions are announced on all speakers. We spend a lot of effort to make all that happen.
I want to know why the fire alarm didn't do that.