How this medical was announced to the world is not really worth 2 pages of arguing. I'm sure ATC are smart enough to assist you if you tell them that you have a medical on board.
Declaring an emergency can also help with the little legalities ( for the CVR and tapes) of dumping 80,000kgs of fuel over Victoria or alternatively landing a tad overweight. I don't have the info as to which option was taken.