This week, the age-old excuse "I'm stuck in my comfort zone" is addressed as contestants are pushed out of their comfort zones by switching trainers for the week. The red team works out with trainer Bob Harper, while the black team burns calories with trainer Dolvett Quince. And one trainer gets out of his own comfort zone by trying ballet with his female contestants! Also, the teams get down and dirty in a 70-foot wide mud pit, filled with various weight plates they have to find in a messy challenge that will give one team a big advantage. Then it's time for the weigh-in, followed by an emotional elimination sending one more player home.

The teams are dissolved, leaving the nine remaining players to compete on their own. Later, a tug-of-war contest finds the contestants competing for a shopping spree with Jessica Simpson; a trainer helps a player face her fear of heights; and a contestant turns the tables on a trainer.

The contestants go to Hawaii to test their ability to lose weight during vacation. During the trip, the players face off in a trivia contest and a challenge involving tikis and leis. Later, surfer Bethany Hamilton gives the gang surf lessons.