 When Shannon is eight , her father marries Sabrina Carlyle ( Lindsay Frost ) , and she spends much of her adolescence with her stepbrother Boone . She studies ballet and , as she gets older , teaches dance classes to young girls . When she is eighteen , Shannon 's father dies in a car crash . He did not have a will prepared , so all of his money and property goes to his wife . Sabrina refuses to help Shannon financially , despite Shannon winning a prestigious yet non @-@ paying internship to the Martha Graham Dance Company in New York . Unable to come up with the money herself , Shannon moves to France for a short time to work as an au pair . Shannon later forms a plan to con her stepbrother , Boone Carlyle , into giving her some of the inheritance she rightly deserved . Playing on her knowledge of Boone 's love for her , she makes it appear her boyfriend Brian abuses her . Boone pays Brian to leave her , and Shannon plans to secretly take half the money . During one con in Sydney , her " abusive boyfriend " ruins Shannon 's ruse after Boone cuts him a check . Boone storms off to his hotel room and plans to return to the States . When Shannon 's boyfriend takes off with all of the money , Shannon goes to Boone 's hotel room in Sydney , drunk , and Boone allows her to seduce him . After they have sex , Shannon tells Boone things will go back to the way they had been before . He expresses anger because , as always , they both know she is in control of their situation / relationship . The following morning at the Sydney airport , Sayid Jarrah approaches Shannon , asking her to watch his bag for him . She deftly obliges , but soon leaves it unattended . Before the doomed Flight 815 takes off , Shannon rummages through her hand @-@ luggage for her asthma inhaler , which Boone casually hands to her . She smiles , the platonic love she has for Boone briefly relieving her of her misery . Six hours into the flight , only moments before the crash , Shannon and Boone are momentarily seen as Charlie Pace stumbles through their row . 
