The shocked Time Lord realises how the base's computer will affect all of their fates, present and future. Fifth Doctor adventure stars Peter Davison and Sarah Sutton.
See all episodes from Doctor Who
50 years of adventure! Join the Doctor for great clips, trailers, news and fun!
David Tennant, Steven Moffat, Russell T. Davies, William Hartnell, Tom Baker and more ..
Sign in to the BBC, or Register