Young Marc getting beaten up. ("White Rabbit")
Before Jack's wedding to Sarah, Jack and Marc, who was to be Jack's best man, were fitted for tuxedos together. Marc was annoyed that he had to wear a real bow tie instead of a clip-on tie.
Marc with Jack ("Do No Harm")
Jack asked Marc if he felt all right about being his best man, as Jack knew he didn't like talking in front of crowds. Marc said he would be fine after eight beers. Jack warned Marc that Sarah would know that he was drinking, and Marc joked that he would brush his teeth. Jack told Marc that he could still back out of giving the speech, and Marc told Jack that he could still back out of the wedding. ("Do No Harm")
At the wedding rehearsal dinner, Marc introduced Sarah as "the future Mrs. Jack Shephard." She then told the party the story of how she met Jack: the car accident, her broken back, Jack's promise to fix her, and his miraculous success. Because of all this, she said, she would dance at her wedding. She finished her speech by toasting Jack as her hero. ("Do No Harm")