I believe all such power-related items on the a/c have an individual breaker that may be pulled manually.
That there wasn't a "gear down" data packet bodes seriously ill, I think. If that's correct, it would've had to belly-in somewhere, on the ocean or land. That the Mal-Asians probably aren't capable of mounting a dredging operation is a pretty strong indicator why the USN dispatched such a ship toward the Indian Ocean.
Would that be roughly where Muzzies surmise OBL's carcass to have been sent to Davey Jones' locker?
HF
There certainly is a resettable breaker per power consumer, but not necessarily per every little function. The control panel surface is not infinite. If a pilot is not perfectly aware of what system he is messing with, he'd be well advised to not touch that breaker. An airmchair pilot (terrorist) may not know such details. One needs a user's manual on 777 to find out exactly what breaker would control that function, and whether it is also controlling something else that the pilot would rather not disable.