When Clara is in the Doctor's room of trinkets she finds the cot the Doctor told Amy he slept in as an infant. She also picks up one of the toy TARDIS' Amy made as a child.
When Bram removes part of the TARDIS console, the past leaks through. Heard, in order, are the voices of Susan Foreman in An Unearthly Child (1963), the Third Doctor and Jo Grant in Colony in Space: Episode One (1971), the Eleventh Doctor and Idris in The Doctor's Wife (2011), the Fourth Doctor in The Robots of Death: Part One (1977), the Ninth Doctor in Rose (2005), Martha Jones in Smith and Jones (2007), Amy Pond in The Beast Below (2010), Ian Chesterton in An Unearthly Child (1963), and the Fifth Doctor in Doctor Who: Time Crash (2007).
This episode is only the third time since the shows revival that the areas of the TARDIS outside the control room have been shown.
The rooms that Clara comes across on her initial exploration of the TARDIS are the Doctor's workroom, an observatory, an indoor swimming pool, and a library.
This is the first time the whole of the Eye of Harmony has been seen.