Whitebeard aims to take down the whole of Marineford and orders his crew and the other pirates to flee. Ace gives his final, grateful farewell to his captain before trying to escape as well. However, Akainu tauntingly mocks Whitebeard, and Ace, feeling angry and insulted on Whitebeard's behalf tries, to take him on. But it is quickly apparent that Ace is outmatched, and when Akainu aims to land a fatal blow on the now exhausted Luffy, Ace takes the hit for his younger brother instead. (thetvdb.com)