Planet (The Gunpowder Plot)

A dimensional lesion that led to a cavern on this unnamed planet appeared inside the Doctor's TARDIS when the TARDIS collided with a Rutan ship. While passing the sonic screwdriver to the Eleventh Doctor, Rory Williams accidentally threw the screwdriver through the lesion and the Doctor sent him through the rocky cavern to get it back while the Doctor remained inside the TARDIS making sure the lesion didn't close. (VG: The Gunpowder Plot)