Real world interface The real world interface , on some occasions referred to as the door , was the part of the TARDIS which connected the outer plasmic shell of the ship to the interior . Functions . By crossing the dimensional threshold of the interface a person or object underwent an instantaneous translation from the ongoing space - time continuum occurring outside the vessel to that pertaining in the separate micro - environment within ( or vice versa ) . This process was known as " going into the TARDIS " or " coming out of the TARDIS " . ( TV : " Logopolis " ) Depending on how the chameleon circuit configured the TARDIS , the real world interface might actually resemble a door or doorway . On other occasions , the real world interface might not be visible at all , making the TARDIS appear to have no obvious entrance or exit . Opening the doors while the Doctor ' s Type 40 was in transit usually had grave consequences , ( TV : " Planet of Giants " , " Warriors ' Gate " ) but once materialised , the TARDIS force field usually protected the interior even if the doors were opened to a hostile environment . For example , if the doors were opened in a vacuum , the interior of the ship would not undergo explosive decompression . ( TV : " Four to Doomsday " , " The Runaway Bride " , " The Stolen Earth " ) Real world interface of the Doctor ' s TARDIS . The Doctor ' s TARDIS originally had what appeared to be two sets of doors , the police box doors of the outer shell , which were manually operated from within and without , and a pair of more substantial doors covered on both sides in the usual roundel motif . The inner doors were usually power - operated — operating a switch on the console or opening the outer doors manually caused the inner doors to open automatically . A dark void linked the two sets of doors . The pressure exerted by the door servos was not especially great ; a Cyberman was able to force the doors open against the mechanism . In the event of a total power failure , the doors could be cranked open and shut manually . ( TV : " Death to the Daleks " , " Earthshock " , PROSE : " Full Circle " ) By the time he met Rose Tyler in his ninth incarnation , the Doctor ' s TARDIS had a simpler arrangement , with the police box doors of the ship opening directly onto the console room . The doors were usually manually operated during that era . Despite the appearance of simplicity , the Doctor believed the protection provided by the doors when closed to be exceptionally strong , telling Rose that " the assembled hordes of Genghis Khan couldn ' t get through that door — and believe me , they ' ve tried . " ( TV : " Rose " ) Queen Elizabeth I once pointed out that while the Tenth Doctor ' s TARDIS was bigger on the inside , the door wasn ' t , and her head was nearly taken off when the Doctor rode out of the TARDIS with Elizabeth on a Zygon which took on the body - print of a horse . ( TV : " The Day of the Doctor " ) On one occasion , when the TARDIS ' exterior shell shrank , so did the door on the interior . ( TV : " Flatline " ) River Song revealed that the future Doctor she knew habitually opened the TARDIS doors by clicking his fingers , something the Tenth Doctor said was impossible . However , shortly after her death , he tried this and found it worked . ( TV : " Forest of the Dead " ) He did not routinely use this ability in the rest of this incarnation , although his eleventh incarnation did later demonstrate it to Amy Pond . ( TV : " The Eleventh Hour " ) The real world interface could vanish entirely with no way into or out of the TARDIS once the TARDIS entered siege mode . This could not be circumvented manually , and required additional power to " turn it off " . ( TV : " Flatline " )