Kate and Sawyer stay at the second triangulation point , while Sayid go to the third . After learning of Jack 's situation from Sawyer , Kate go to help , leaving the job of turning on the signal to Sawyer . Charlie squeeze through an opening at the cave and find Jack , but while doing so , the opening collapses and trap Charlie and Jack inside . Charlie hesitantly pop Jack 's shoulder back into place at Jack 's request . Jack correctly guess that Charlie is suffering from withdrawal , and Charlie assure Jack he 's okay . Kate desperately try to dig them out along with the other castaways , while the two worry about losing oxygen . Charlie see a moth which lead him to an opening and the pair dig out of the cave .