Candler, doesn't the 747 have the same thing as a basic 777F with a main deck fire warning. Arm and activate the appropriate compartment switches and get a controlled depressurization? Obviously a rather cheap way to possibly buy some extra time at altitude if a suitable divert is not conveniently close by.

I realize that's probably not going to do much with a runaway battery situation, just curious if that's an optional system Atlas went without.