The GoodItachi share their first conversation together. Kisame warns Itachi that he will have no problem betraying him and eating him for dinner, yet Itachi doesn’t really care; I wouldn’t either if I was Itachi.
So after the flashback is over, we all have a pretty good idea knowing what fate awaits our shark ninja friend. When surrounded by enemy ninjas with nothing else to do, of course there is only one thing to do, and that is to feed yourself to a pair of your own summoned sharks! Kisame doesn’t want anyone to know any of his information, so the only way to keep it safe was to kill himself. However, he had one final thing up his sleeve, and that my friends was the scroll. When opened it trapped everyone in a water prison with their own personal shark, leaving the scroll to be carried away by a shark in it’s own water prison. With that the shark swims out to sea and the enemy wins, great.