I meant good that the masks wouldn't contribute much. The rest of that other thread sounds fairly horrific.
It can be. Even what starts as a small fire when parked at the gate, within seconds can become a cabin conflagration and a cabin full of smoke.....in less than 30 seconds. Reference Delta 1558, the 727 parked at the gate in SLC on a stopover in 1989, which had a fire ignite in the EE bay. Only 12 continuing-pax were onboard at the time, along with the flight/cabin crew, and even those all barely made it out of the aft airstair. Had there been a full or nearly-full plane, there would certainly have been fatalities. And that's just a jet parked at the gate with no engines running and exits already open.