Synopsis: To their incredibly great fortune, the Doctor and Jamie see that they're close to what used to be a scooter factory in the underground city. Hopping on a pair of scooters, they fly away from the approaching Quarks.
Unfortunately, the giant wasps have found a way to squeeze through the crack that leads from the planet surface to the underground city, below. The now angered wasps seize upon the first movement they see, and start attacking the Quarks instead of Jamie and the Doctor.
Notes: If this story structure isn't by now seeming awfully familiar, then clearly you didn't read the preceding adventure, "Invasion of the Quarks". Apparently, the Doctor and Jamie's big idea in Season 6B was just to let their enemies fight each other until they're the last two standing.