CASA's response to this one will indeed be very interesting.
Notwithstanding circuit breakers, there are few irreversible switches/selectors in the flight deck of any aircraft, ADIRU rotary switches are definitely among the 'do not touch' while airborne unless specifically directed to in accordance with FCOM. The captain saying 'yep' to this action whether confirmed or not is telling.
I can appreciate that there are different AOC's involved with this 'incident' and the 8501 crash but CASA will also have to address public safety concerns and these two pilots who displayed a complete lack of rudimentary airmanship may well be beyond re training. On the day in question they certainly had no place up the front of an passenger aeroplane, let alone a wide body RPT jet over metropolitan Sydney.