Nothing too exciting just the right engine showing absolutely no oil level whatsoever so the engine was shut down about 15 miles south of Nokin (possibly to protect the engine itself)
Interesting point though, is that
IF there are no other supporting parameters, zero oil quantity, is categorically not a reason for engine shutdown on RB211-535 as fitted to B7575 as per Boeing and RR operating instructions. e.g there is no QRH item.
However, crew may have reported just the basics at that stage with out elaboration and once the engine was shutdown, then a Mayday is quite correct IMHO.