I just read somewhere that the cause of the initial problem was water getting into the generators...now I don't know how all 4 could be lost...but, like murphy said: if it can happen, it will happen.
I hope that we take this situation seriously. It is possible to lose everything...to be down to battery with 45 minutes of power...time to think how to use that time. Over the USA, land at the first available proper airport.
BUT over the ocean, at night, hours from landfall...ouch.
if in the clear, I would get out a mayday, request an intercept and escort and advise powering down and an ETA for the next radio contact. Certainly there are so many concerns and potential scenarios.
There was a delta 767 that had the same problem, crew landed ok. AND YES, the RAT didn't work! 747 doesn't have the RAT to being with.
if NOT in the clear, you have to keep the gyro working somehow.
*(I suppose someone could use the cat system...joke here)