Ya know that sounds highly plauseable aided by the jet fuel which probably burst the oxygen tanks.
Powdered alumium and powdered rust with an oxidizer= thermit.
Potassium cloride and finely powdered aluminmum equal parts =flash powder. Solid magnesium burns hot (and bright)so will aluminum if flaked and it gets hot enough ,....
Commercial airliners cabin pressurization is run off of the engines, the emergency oxygen system is generated by a generating canister not a high pressure tank system.