Polar742
All the responsibility none of the authority
"American Airlines says one of its jets made an emergency landing on an Aleutian island after a fire warning light went off."
I don't fly these aircraft, but I've never heard of having the fire warning light go "off" instead of "on" to indicate there is a problem. It just seems like it would be much more difficult to detect, also what if it was something simple and non-emergency related like the bulb burning out.
All I know is that along that route there are not many places to put a big airplane.
As has been pointed out, it's not a time to play the "It's probably an indication" game out over the North Pacific. The fire systems are very reliable and will indicate if there is a fault in the system, so if you receive and indication and there is no fault message, it's time to get the engine secured and get the jet on the ground.