Comms/electric failure upon full engine failure

I've just flown a sector online from Paris to Gatwick (280nm) in the 747-8x.

I loaded up reserves of 18000lbs but with holding and a late go around, on the second approach I was down to 3000lbs and the engines cut out at around 2.0D/1000ft! With them went all comms and electrics, meaning I could not call mayday! With full flap at 150kts I had to crash land short!

Are comms and most electrics meant to cut with full engine failure? Doesn't seem very safe if so, or is there some emergency switch I missed!?!?

Thanks!

Ben Thomson