Watching video taken by a passenger of the plane and other passengers standing around, I noticed what appears to be a heavy stream of water from the far side of the plane. At this point the fuselage is still intact (meaning no visible fire damage seen from the LH side). Yet the plane ends up like so many with the top of the fuselage burned. Is this likely from fire going through the air ducting from the engines going through the wing into the fuselage top where the ducting for cabin pressurization is located? Is there a fire stop in the pressurization system to prevent a fire from entering through the ducting? Trying to understand how the fuselage burned when several minutes after the crash there is smoke on the RH side but the fuselage is not yet involved.