The Barracks battle in 2004 was the fight between the mercenaries and the alliance of Locke's faction, with help from the Monster. The battle resulted in a crucial defeat of the freighter mercenaries at least 4 of Locke's people. Notable characters who died in the battle include Mayhew, of Martin Keamy's mercenaries, and Jerome, a blonde woman, Doug and Alex from Team Locke.
Charles Widmore had sent his people on a mission on the Kahana. ("The Other Woman") The freighter people were divided into what seemed to be three distinct factions: The crew, the Science team, and the mercenaries. Frank Lapidus transported Keamy and his troops to the Island by helicopter. The mercenary team observed Rousseau, Alex and Karl and established a hasty ambush. After killing Rousseau and Karl, they captured Alex and brought her to the Barracks. ("Meet Kevin Johnson")
Doug is shot and killed.
After receiving a telephone call which repeated "Code 14J," Locke told Ben about the call. Ben reacted hastily and fearfully, giving weapons to Locke and Sawyer and moving to another house, which was more easily fortifiable. Sawyer, refusing to heed Ben's warnings, ran across the cul-de-sac to ensure Claire's safety. On his way, he met Doug, and warned him to get inside. However, Doug was soon shot in the chest by Redfern, a mercenary hiding in the jungle.
A blonde woman immediately ran out into the open to see what was happening and was shot. Jerome soon followed, and despite Sawyer's warnings, was shot as well. Sawyer continued on the way to Claire's house, dodging rapid gunfire using a picnic table and sheer luck. However, before he was able to reach Claire's house, Kocol fired a rocket at her house, blowing it up and knocking Sawyer down.
Claire, miraculously survived, and was carried back to the fortified house, where Hurley shattered a window in order to keep the door from being unbarricaded, but still allowed Sawyer to enter. While they discussed strategy, Miles appeared at the door with a walkie for Ben. Ben took it, and found that Keamy was on the other end, who instructed him to look out his window. Upon looking, Ben saw Keamy standing outside, alone. Ben refused to surrender, and, at Keamy's order, Kocol brought out Alex, Ben's daughter.
Keamy prepares to shoot Alex.
Forcing her onto her knees, Keamy held a gun at her head and demanded Ben's surrender. Ben did not believe that Keamy was going to shoot Alex, instead refusing to come out and bluffing, denouncing Alex as his daughter, stating "I stole her as a baby from an insane woman. She's a pawn. Nothing more." Keamy, however, shot Alex in the head, killing her, before retreating with the rest of his mercenaries back into the forest.
Mayhew is grabbed by the Monster.
Ben, in shock, entered a secret room, and was not seen for a short period of time, while Sawyer, Locke, Miles, Hurley and Claire waited anxiously in the house. However, Ben soon returned, stating that they would need to flee into the forest at his command in a few minutes. Soon, the Monster arrived, having been summoned by Ben, and attacked the mercenaries hiding in the woods while they try to shoot at it. Mayhew attempted to escape, but was dragged back into the fray by the monster, becoming seriously injured in the process. Ben, after saying goodbye to his daughter, followed Hurley and Locke into the woods toward Jacob's cabin, while Miles, Sawyer, and Claire and Aaron set off to return to Jack's group at the beach camp.
Having survived the Monster attack, Keamy and the rest of his mercenaries (carrying a seriously injured Mayhew) set off back toward the helicopter, where they met with Frank. He then returned them to the Kahana. ("Something Nice Back Home") After their arrival on the Kahana, Mayhew died. Keamy unilaterally opened the mission statement for the "Secondary protocol" Gault's objections resulted in Keamy killing Gault before leading the mercenaries, excluding the deceased Mayhew, on a final mission to "torch the Island." ("Cabin Fever")
Sometime shortly after Ben left the Island, Richard Alpert came to the Barracks and buried Alex near the spot where she died. This was revealed much later, after Ben returned to the Island in 2007 and walked by the spot with Richard and Miles, and Miles sensed Alex's presence, forcing Richard to tell Ben that he'd buried her there. ("What They Died For")