hes a biologist. he was proving that the "nose rubbing" method of putting sharks to sleep (through catatonic stasis) works. Putting sharks in that state helps researchers when they collect blood samples and stuff like that, cause the animal is basically asleep. it can't feel or struggle. He also proved that caribean reef sharks LIKE to be put to sleep through nose rubbing. He did this when the shark was catatonic... u cant do this when a shark is awake.