Shark incidents are two types. One is attacking what it believes to be a turtle or seal. After one bite, sometimes fatal to the victim, it flees, leaving its wounded prey, realizing a mistake in identity. The other is encounters with spearfishermen. The shark is not attacking the human but going after his prey. The divers gave up their catch and got themselves out of there. Hard to imagine any other response. However, that shark has now been rewarded for its behavior and will do it again.