[Casseres]

I imagine something like this is going through the heads of many people:

Oh, an alarm is going off. Is this a drill? Must be, I don't see anyone running or anything on fire. No one is telling me that I have to leave, so I'll just stay right here and carry on with my business. I don't really want to go outside only to wait 15 minutes to half an hour until they tell me the alarm was an accident.

Solution: Have someone go to the fire panel, see where the alarm was set off, go to the place where the alarm was set off, verify there is an actual emergency, make a live announcement on the PA system telling people to exit the building.

At the minimum, telling people to exit the building, even if it's an automatic recording that plays when the alarm was set off, is the best way to get people to comply. Telling people to exit is much more powerful than a noise and having people decide for themselves whether or not to exit.