How does an onboard fire disable all of the comms and depressurise the aeroplane so suddenly that neither pilot was able to go onto oxygen and continue to fly ther aeroplane which patently remained "airworthy" for many hours afterwards?
It is probable that the pilots while being distracted by the various alarms going off failed to immediately don their oxygen masks and commence an emergency descent to 10,000 feet following the sudden loss of pressure as is standard procedure. The high probability is that they were therefore rendered unconscious within 30 seconds and subsequently died as the aircraft continued to fly on as has happened in previous known accidents caused by pilots suffering hypoxia.
Sorry, but that's just not credible. Going onto oxygen as a 1st response is a practiced and drilled routine.
PDR