Exodus (2) - S1-E24
Revealing mistake: On their way back to the hatch with the dynamite, Kate, Jack and Hurley run from the "monster" but Locke runs toward it. When he lands on his back the shot cuts away to the "Lost" logo floating onscreen. When it cuts back to Locke, in this shot the bruise is over his right eye, instead of his left. The shot is flipped. (00:44:50)