Temporal grace

Temporal grace was a term used to describe the state in which the interior of TARDISes existed. Supposedly, it ensured that no weapons could be used inside the environs of the Doctor's TARDIS. (DW: The Hand of Fear, The Invasion of Time) However, on other occasions, it seemed that no such defense existed. Cybermen (DW: Earthshock, Attack of the Cybermen) and a Dalek, for example, discharged their guns in the TARDIS. (DW: The Parting of the Ways) Nyssa presumed the grace broken when the Cyberman was able to fire weapons inside the TARDIS. The Fifth Doctor replied, "Nobody's perfect." (DW: Arc of Infinity) Later, the Seventh Doctor said that the State of Grace circuit still needed looking at. (NA: Cat's Cradle: Time's Crucible) After Mels shot the TARDIS console, the Eleventh Doctor admitted that temporal grace was a "clever lie". (DW: Let's Kill Hitler)