I just realized that NONE of the crew members report hearing a smoke detector. Were the smoke detectors connected to the wiring system, or run by batteries?
If the smoke detectors were connected to the wiring system and DIDN'T function as they should, THIS WOULD INDICATE THEY MIGHT HAVE FAILED BECAUSE THE WIRING SYSTEM SUPPLYING THEM WITH VOLTAGE HAD SHORTED OUT AND CAUGHT FIRE!!
Mystery solved?
I’m thinking that smoke alarms are required to run on batteries - specifically because of the risk of a general power failure.
But - I do not know that for certain.