This is basically what would happen if you heard this in your haunt if your setup properly to an extent. However proper haunted house safety and fire protection precautions can remove the need to freak out. The main house lights should be setup so they can come up immediately if you here any sort of emergency call over your radios. Now if you have properly trained your actors and haunt workers and placed proper fire equipment throughout your haunt you are not freaking out like stated. Instead your checking over the radio to insure everything is under control. If for some reason a animated prop or electrical setup causes a fire you want your workers to know how to react and handle this. Not only must they know that everyone needs to be evacuated but it would also be good if there was some sort of fire extinguishing gear near any prop or set piece that could cause this situation so that an actor or worker can react quickly to extinguish the fire.
Now if you work with the local fire department not only can you get fire extinguishing training for your workers but often times you can get them to come out and walk you through various scenarios that could happen and get some semi-real practice for your workers in what they would need to do in case a fire broke out. This makes a big difference having trained workers compared to someone who has no clue how to operate extinguishing equipment and not every case is the same or can the same equipment be used so proper training is great.
The majority of fire codes require there to be a fire sprinkler system and proper fire extinguishing equipment throughout the building but having extra at each major electric prop never hurts and could prevent issues getting to the point where the overhead sprinklers will have to come on. Also often times you can get a volunteer firefighter or hire an off duty one as part of your security like is often done for regular security with the local police. This helps with response time if something serious comes out and allows a professional to be able to help out when something does happen.
Now another thing is having cameras and proper mapping out of personnel so you know where everything is going down at and can direct proper evacuation and direct safety personnel to the proper location. If you do not have cameras make sure everyone is familiar with the layout and knows the way in and out to the various locations so you can direct them, this makes a big difference not only for safety precautions but for directing the relief of workers for breaks and for any minor difficulties or malfunctions you may have during operation.
Is there anything you have done with your haunt to help insure it’s safe operation related to fire protection?
Disclaimer: I am not a fire code official or fire fighter nor am I a legal council so make sure to consult with your local officials about specific codes and regulations as every location differs slightly and some have much more required for fire protection.