There are nine people left in the final challenge, and they're all going to have to run through the tunnel in order to get to the other side. Engorgio is freaking out because he remembers that law five says that if he misses his footing, the tunnel walls will crush him into pieces. He's going to head off first, after everyone else, and then he'll have to wait for the light source to tell him where he's supposed to be. The light source is calling him, and he can't figure out what to do, so he runs off to find it.