"For all we know they might have had reason to THINK fuel was pooling under the aircraft....."
Wouldnt given the knowledge of pooling fuel under the aircraft combined with a known fire give impetus to the "Lets get the f%$^# off this aeroplane" argument.
The assumption in the stay onboard argument is that the RFF WILL SUCCEED. As anyone who has been involved in fire fighting knows, it is not until you are standing around eating sandwiches after the fact that you can say with any certainty that the fire is under control.