Passenger floor area, could be a high pressure pump leak, fuel line to lh fuel rail leak, battery failure / acid leak which can (and does) drip down onto the electrical connections and main harness containing the power source for the eas compressor. Also possible is an oil leak onto the engine pipe/ turbocharger, or foreign matter igniting like rodent nest etc.
A very sad loss and a lucky escape by the driver.
Jc

