If the alarm goes off, get out of the building calmly. Even if it *might* be fake, suck it up and go.

Do not take elevators. They are programmed to not move when the system triggers.

This may seem obvious, but, again, I have literally seen people do the exact opposite.

Doors are programmed to shut automatically when the alarm triggers. They don't lock. They're just closed. You can open them.