There’s nothing you can do other than stay in your seat and keep out of the way.
Because as soon as you mention "fire" you'll get a bunch of dumb fucks panicking themselves so hard they're going to behave completely irrationally (like attempting to rip open the emergency doors which IS possible at low enough altitudes) - or manage to induce legitimate medical problems. Heart attack for the older folks, dyspnea up to actually going unconscious from hyperventilation for the younger folks.
The Denver airport fire this month was an object lesson. A panicking mob apparently ignored instructions and went out the wrong emergency exit door, onto the airplane wing, where they stood over the flaming jet-fuel smoke with no way down.
(The other doors had slides).
And yes this shit has happened in the past. Panicked people are uncontrollable and in a critical situation, priority #1 is to avoid panic to rise at all costs because panicked people can turn a critical situation into outright disaster.
Crowds can do dumb shit in a self reinforcing loop.