Season Four, Episode Nine: "We're Not At Charm School..."
A.K.A. Millie's Heart Of Darkness
Millie and Chuck, promoted more for their clichÃ©d, ho-hum characteristic ("Virgins") than for their truly weird one ("Dating 12 Years And Kind Of Still Thinking About It"), were a gender reversal of the typical type-A couple, in that Chuck was mellow and not particularly cutthroat, while Millie would open your chest and remove your heart with a knitting needle while insisting that she was a nice person. Her freakish devotion to victory manifested, in part, in a habit of spending her pit-stop time eschewing sleep (and apparently showers) to study maps and guidebooks. As you can imagine, this led Millie deeper and deeper into exhaustion, ill temper, and -- yes, we'll say it -- filth.
In Malaysia, with five teams left, having skipped all sleep for two consecutive nights, Millie and Chuck ran into the one thing they couldn't afford: a leg that didn't start with a long plane flight they could sleep through. What's more, the leg forced them to do all their own driving and navigating, rather than allowing any reliance on cabs or trains. They got lost during a 145-mile trek to a coconut palm plantation, and then they got even more lost when they left, so Millie and Chuck were clearly doomed.
Meanwhile! Millie and Chuck's mortal ultra-enemies -- the Sharks to their Jets, the Simpsons to their Cosby Show, the "tastes great" to their "less filling" -- were the snotty, self-involved, sometimes spitefully entertaining Kelly and Jon. And on this leg, Kelly and Jon made a series of early mistakes themselves, leading to a quite reasonable decision to go for the Fast Forward. Except! Studly (then-)couple Chip and Reichen accidentally stumbled across the Fast Forward before Kelly and Jon could get to it, so, having wasted the entire trip to the Fast Forward, Kelly and Jon were...clearly doomed.
What happens when two teams are clearly doomed? In most cases, one of them is stunned to arrive at the pit stop and learn that they aren't last. In this case, however, a producer's wet dream came true, and though they'd followed very different paths to get there, Millie and Chuck and Kelly and Jon managed to run smack into each other at the last task of the leg, a Roadblock featuring a wild ladder-climb inside a cave. The tension was close to unbearable, complete with Millie madly sucking her inhaler as Chuck and Jon did the climbing. The teams wound up bumper-to-bumper driving to the pit stop, where Kelly and Jon grabbed just enough of a lead that they got to the mat before a dirty, used-up, utterly miserable Millie and Chuck, who were eliminated.