How many people in their own house would jump out the window at the first SMELL of burning?
In my house there are four exits for the three occupants -- compare that to a narrow tin tube with fifty semi-obese folks clinging to their cabin baggage between me and the nearest exit.
Of course in my house I do know what the smells are and where they come from and act accordingly.
In a commercial building when the alarm comes on and there is no communication within 15 seconds, I take the fire exit, alarmed or not.
The SLF are generally not educated in the various fumes or tailpipe fires; so prompt communication is key. If the crew fails to keep them in the loop, the proactive ones will be operating the exits.