This is all about Sayid and the question "If you could go back in time and kill Hitler, would you?" In the case of Lost, that would be Ben. So, it's all leading up to when Ben helps Sayid escape captivity and the moment of truth, does Sayid kill Ben? The answer is Yes. Everything leading up to the ending was great, especially seeing how Sayid was caught and handcuffed getting onto the plane that brought him back to the Island.