I would think it would be very difficult for a DM at Coz, with the currents and a drift dive operation, to surface with a sick diver, get the diver safely on board, and then re-locate the diving group. I am very surprised the DM did not send the diver's buddy to the surface with the diver, instead of doing it himself, or take the whole group up until the problem was resolved. The focus should have been on the distressed diver, even if that meant other divers did not get the dive they had hoped for or expected. If I am a dive buddy, I fully expect to go to the surface with a buddy in distress, do what is necessary to get the distressed diver on board, and then likely have to end my own dive, especially at Coz. My heart goes out to the young DM because he is going to have to carry the burden of his decisions for the rest of his life.