"SS Lost-tanic" is an orchestral piece from the Season 6 soundtrack.
The timer on the Man in Black's bomb begins counting down even faster, and Sawyer steps back, horrified. Sayid gives Jack instructions on how to save Desmond. According to Sayid, Jack will be the one to replace Jacob. He then grabs the bomb and runs from the others to the far end of the sub. It detonates in his hands, blasting a hole in the hull and killing him.
The entire submarine shakes. Frank tries to investigate what happened, but a steel door blows off its hinges and hits him. It lets in a torrent of water that begins to flood the vessel. Jin sees wreckage covering Sun, and Sawyer runs to help them. Jack pulls Kate from the water and hands Hurley an oxygen tank so he can surface with her. Hurley asks after Sayid, and Jack yells the sad truth at him.
The three remaining men manage to lift a cabinet off Sun, but pipes still cover her, and more pipes soon fall on Sawyer. Sun begins to realize she will not escape. At Jin's request, Jack leaves with Sawyer and takes the remaining oxygen tank with him.
Jin keeps pulling vainly at the pipes, although Sun knows it's no use. She asks him to leave for safety, and for a moment, he looks longingly toward the exit. But he stays, telling her in Korean that he will not leave her again. They kiss.
The scene shifts to the outside of the submarine, which is still sinking. The last air bubbles leave its breached hull. Inside, a red light flashes as Sun and Jin's lifeless hands drift apart.
Locke's motif plays early on in the piece, and is later followed by the destiny motif. This theme leads into a short riff from FLocke's theme. This is followed by a dramatic variation on the main theme. The submarine theme blended with Locke's motif plays afterward.
Full list of appearances
The piece's final section plays during the "Previously on LOST" segment of "What They Died For". This is the only time in the show that it plays.
The title references the RMS Titanic, a luxury liner that sank in 1912. The film Titanic featured a tragic romance that ended when death separated the hands of a couple in the water. The couple were named Jack and Rose, and this episode coincidentally jokes about Jack flirting with Rose. The track appears to be erroneously titled "Get Lost-Tanic" on the US iTunes store.