When it started, I was just about ready to leave anyway. No one in our office seemed to think that we needed to leave, I was listening to Modest Mouse instead of the announcements so I decided to wait until the commotion had ended.
After about five minutes of announcements, some people1 decided that we really did need to participate by walking down a few flights of stairs. I guess no one in our office was very concerned about being burned to a crisp or facing disaster. By the time we'd walked down a couple flights of stairs2, the drill was over.
I just kept going since I needed to drop some application materials on campus. In any case, I think that's not a bad disaster policy.
(1) our fire marshals?
(2) instead of the required four.