The trainers enter the gym and learn about this newest scheme. Jillian tells us that it doesn't get any better than immunity -- people want it more than cars or a bunch of money. If anyone is going to lose two percent of their body weight, they must work out. Thus: beatings. Ashley tells us that the stakes are high for her, because she had low numbers last week. She's strategizing about when she should go for immunity. Jillian chooses to focus on Sunshine this week, and notes that she has a lot of potential. Sunshine tells us that Jillian's workout was really hard. She seems to do everything well and without complaint, though. Jillian notes that there's a real spark in Sunshine that she might not be fully aware of. She tells Sunshine that she needs to be more rooted, focused, and grounded, and see herself winning this thing. Sunshine jumps in and out of tires, and because Jillian believes in her, she now believes that she can go all the way, too.

Bob, meanwhile, gives Melissa some attention. He was excited to talk to her, which was foolish in the first place. He's disappointed when all Melissa wants to talk about is the game, and her strategy to get immunity. Bob tells her that his job is to help her, and make sure they discover who she is. She can play the game, but can't forget that everyone who has ever played the game on this show has also worked their ass off simultaneously. He doesn't want her to lose sight of what The Biggest Loser is really about. Bob interviews that Melissa's a tough one -- she likes the play the game, but if you play the game you have to get ready because it can bite you in the ass. He tells her that she's there to change her life, and when she starts thinking in terms of all she's accomplished she'll be unstoppable. Currently unstoppable is her mouth, and her craziness. She goes through some litany of events -- including the phrase "boo ya!" -- that will result in her being in the final four. God, I hope they vote her ass out today.

Ugh, and then as if Melissa isn't already enough to deal with, the contestants get a visit from Dr. Huizenga. He wants to talk to them about whether the two percent challenge is safe. If you lose all the weight in terms of fat it's perfectly safe, he says, but if you lose muscle, bone and water (especially critical electrolytes) it's not only very dangerous but potentially lethal. Calories are important. You can't work out intensely and eat nothing -- fat needs kindling to get logs burning. That kindling is nutrients from food. This is Dr. H.'s only message. He's much more pleasant when he isn't telling someone they're going to die.