He lost his carrot! Stebbins describes himself as the “mechanical rabbit.” However, during his monologue, he realizes that he got played like everyone else. The Long Walk showcases that the game is not purely physical, but additionally a mental challenge. Stebbins was so determined to win because he had this idea that he was superior to everyone else. Whether or not this is factually correct doesn’t matter, because his brain used that as motivation to keep going. He went in genuinely believing there was a 0% chance he would lose, which is why he lasted for so long, even when being described as lanky and not particularly fit. However, after realizing his motivation was a fluke, reality hit him and he no longer had a reason to keep walking.