What happens during Toby and Ezra's trip to Disneyland?

While Toby, Ezra, and some of their friends are at Disneyland, Toby and Ezra sit on the very back seat of the ride. The boy in front of Toby stands up as the ride is entering a tunnel, and his head is knocked off his body. Toby catches the head and has little choice but to hold it until the ride comes to an end.