I'm a floor captain at work, which is a glorified term that means I leave after I've swept half a floor for people who won't leave when the alarm sounds. People are pretty predictable - 95% move out quickly, then a handful choose to ignore and stay answering email, tinkering with computer hardware, occasionally talking on a conference call. I note their room numbers and they get reported to their managers and to security / fire responders, but no consequences afaik. I would leave immediately if I didn't have to do the fire warden thing, I've seen how fast a fire can do its business.

Boeing has a really good evacuation plan - they operate immense airplane factories, where an alarm could go off in Sector AA-25, and if they evacuated the entire plant for every call then productivity could be crushed, thousands of man hours lost. They localize their evacuations, and step up their fire fighting response. They also do something pretty cool with their fire wardens - they train the entire employee base to react, meaning if you hear an alarm the closest employee grabs the area check list and sweeps people out; everyone is a floor warden, or everyone who wants to take the responsibility. In practice its still the guy who volunteers for the duty, but if they're not there then everyone else is nominally prepared to sweep the area and report to responders. That makes sense to me, I've been out of the office during two actual fire emergencies in two different buildings, and no one was there to do the fire warden job.