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, have discharged their guns in the TARDIS. (DW: The Parting of the Ways) Nyssa presumed the grace broken in regards to the Cybermen having been able to fire weapons inside the TARDIS. The Fifth Doctor simply 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)