According to previews released by CBS, the medical emergency could change the course of the game, which so far has been lopsided with only members of one team being ousted.
For each of the last four weeks, the Matsing tribe has lost the immunity challenge and turned up at Tribal Council to vote out one of their own. Last week , it was Russell Swan's turn to go.
Swan was one of the three returning contestants, who appear to be leading the tribes. All three were evacuated by medical emergency from earlier "Survivor" games.