The Pala Ferry battle was the fight between the Others and the survivors. The battle resulted in an Others victory, however, the survivors managed to kill one of them. The battle was a fight over the Elizabeth sailboat. The boat was initially brought to the Island by Desmond Hume, and was given to him by Libby. During the battle, Sun encountered Colleen aboard the boat, and fatally shot her.
Sayid, Jin, and Sun were using the sailboat to sail to the other side of the Island. There intent was to create an ambush for the Others. Their plan was to use black smoke so that the search party for Walt could find them. The signal fire was initially blocked by the mountains, so they took the sailboat to the Pala Ferry to set up another fire. As Sayid, Sun and Jin build the new signal fire, Sun questions why it is so large. Sayid says that it is so that Jack will see the smoke, but Sun asks him why he is lying. Sayid admits that he suspects that the other party has been captured, and he plans to provoke an attack by the Others in order to capture two of them as hostages and kill the rest. When Sun asks why they must capture exactly two, Sayid replies that it is to make the other one talk. ("The Glass Ballerina")
Sun shoots Colleen. ("The Glass Ballerina")
At nighttime, Jin and Sayid take their positions in the trees, prepared to ambush the Others. Sun is back onboard the Elizabeth, waiting nervously. She starts to hear footsteps above her, and she knows that there are Others on board. She finds a gun, and is encountered by Colleen. Colleen says that she knows what kind of person Sun is, and that she would never shoot. Sun fires the gun, and Colleen falls to the ground. Ivan attempts to shoot Sun, but misses. The gunshots attract attention from Jin and Sayid, and they rush to the dock. The Others see the survivors coming, and open fire. Sayid and Jin fire back, and a shootout ensues. Sun attempts to leave the sailboat, but Tom sees her, and shoots at her. The gunshot misses, but Sun falls into the water. The Others sail away on the Elizabeth, and Sun is left in the water. Jin sees her, and swims to go get her. ("The Glass Ballerina")
Sayid fires at the Others. ("The Glass Ballerina")
The Others rush back to Hydra Island, knowing that Colleen's injuries are critical. Back at the Hydra, the Others get Jack to perform medical care on Colleen. His attempts are unsuccessful, and Colleen dies inside of the Hydra. Her death angers Danny Pickett, and he vows revenge on the survivors that did this, which is shown in his aggression towards Sawyer during the next few episodes after that.
Ivan shoots at Sun. ("The Glass Ballerina")
The Survivors then head back across the Island to the Survivor's beach camp, which is about a day and a half away, without knowing the fate of Jack and his group. ("The Glass Ballerina"). ("Every Man for Himself")