Walls of Confinement (audio story)

 was a 2011 Big Finish Productions audio short story read by Katy Manning. It featured the Third Doctor.

Summary
A young boy's life is in danger as the Doctor comes face to face with a deadly predator.

Characters

 * Third Doctor
 * Liz Shaw
 * Brigadier Lethbridge-Stewart
 * Albert

Continuity

 * This is the second time the Third Doctor has visited a zoo. (COMIC: The Arkwood Experiments)