A horn signals the start of the first heat, and Carl guns the Big Shot Chicken truck forward while Donut clings to him. The Navitron 1000 announces the race details: Carl is the driver, Donut is the navigator, the course is 53 kilometers on flat asphalt, and the environment is supposedly the Caves of the Screeching Death Manatees. Because the truck's headlights do not work, Donut uses a Torch spell to light the road, and Carl catches brief glimpses of several rival teams, including a muscle car, a bearlike runner, a buglike creature, a minivan, a shadowy dog, and a bizarre tumbleweed-like unicorn creature.

As Carl pushes the truck to its limit, he learns the vehicle cannot go much faster than about 70 miles per hour, and the disabled minimap leaves him with little information beyond a simple route line on the GPS. Donut summons Mongo into the cab so she can ride him and see better, but Mongo panics in the cramped space and vomits on the dashboard. While driving, Carl tries to focus on the immediate danger instead of the many unresolved crises from the previous floor, finding brief relief in a problem that seems simple: if he makes a mistake here, only Carl and Donut die, not thousands of others.

That calm breaks when Carl notices a large dark shape ahead that Donut identifies as a cave entrance. At that moment, Prepotente sends a group message warning everyone not to kill or stop opponents from finishing their heat. Prepotente explains his theory that each heat's opponent pool is fixed, so if too many teams are eliminated, later races will have to mix groups together, likely creating crawler-versus-crawler heats. Carl immediately realizes Prepotente is probably right, and the group chat also reveals who chose biological or mechanical vehicles, with Prepotente mocking the mechanical choice.

The warning turns urgent almost instantly. Just inside the cave entrance, Carl and Donut see the minivan overturned and burning, blocking the road, while a bugbear crawls away from the wreck. Nearby, a bus-sized ladybug vehicle is dragged off the road by an enormous manatee, and one burning rider runs screaming before a house-sized screeching death manatee crushes the bug outright. The rider then flashes a notification and explodes, confirming that the race's environmental hazard is real and deadly just as Carl and Donut arrive at the scene.