Seven to One ( audio story ) Summary . Seven Doctors . . . one tricky situation . Will the First Doctor be able to save his future incarnations from a deadly game ? Plot . The Seventh Doctor and Ace find themselves in the realm of Grey Space . The Doctor explains to Ace about the two entities that created this realm . The two entities are bound together in some way and rarely agree on anything . However , in order to do anything , they need to be in agreement . Grey Space is their only achievement . They had pulled the Doctor to them once before , and he used a copy of the game Monopoly to escape , having left the entities arguing about who would go first . The Doctor and Ace find a RWR Mark II android guarding a small , grey door . The entities contact them , and tell them that this is a test . The Doctor will have seven chances to succeed . If he should fail , the entities will erase the Doctor from existence . Ace quickly determines that they needed to get past the android and open the door . The Doctor agrees and approaches the android . He tries to use the default admin password of 0 - 0 - 0 - 0 and succeeds . He orders the android to shut down and it does so . The Doctor and Ace then approach the door . The door has a simple combination lock , and it doesn ' t take the Doctor long to crack it . He opens the door and peers inside . At that moment , the imposter , that was pretending to be Ace , pushes him through the door , causing him to fall into the larger dimension that the door leads to . The Doctor has failed the test , and his first chance is used up . The entities summon the Sixth Doctor and Peri , and inform them of the test and of the Seventh Doctor ' s failure to complete the test . Just like his next incarnation , the Doctor figures that he needs to get past the android and open the door . The Doctor talks to the android and takes advantage of the limited AI in the android . He convinces the android that it no longer has any purpose and should shut down . The android does so . The Doctor cracks the combination lock and opens the door . As he looks inside , Peri pushes him through the door . The Doctor has failed the test again , and his second chance is gone . The entities summon the Fifth Doctor and Nyssa , and inform them of the test and the failure of the other two Doctors . The Doctor uses a Nanoware maintenance engineer card to convince the android to shut down for inspection . The Doctor can feel that something is off , as the test has been too easy so far , way too easy . However , Nyssa ' s complaints cause him to drop the line of thought and he opens the door . As he peers inside , Nyssa pushes him through the door . The Doctor has failed the test for a third time , and only has four chances left . The entities summon the Fourth Doctor and Romana , and inform them of the test and the failure of the other three Doctors . The Doctor uses his scarf to wrap up the android ' s limbs , puts licorice whirls over its visual sensors , jelly babies in its audio receptors , and sherbet in its processing unit in order to disable the android . The Doctor then uses his sonic screwdriver to crack the combination lock . Romana comments that the only reason that the other Doctors failed must have been because she is most likely not with them . The Doctor opens the door and looks inside . Romana then pushes the Doctor through the door . The Doctor ' s fourth chance has been used up , and he now only has three left . The entities summon the Third Doctor and Jo , and inform them of the test and the failure of the other four Doctors . The Doctor convinces the android that Jo is a potential buyer for Nanoware . The android goes into a marketing mode , and the Doctor tells it to demonstrate the effectiveness of the anti - matter rifle by shooting it at the floor . The android proclaims that the anti - matter spread will continue on forever , so the hole will go on for infinity . Jo points out that she can see the bottom and when the android goes to look , the Doctor knocks it into the hole . The Doctor then uses his sonic screwdriver to crack the combination lock . He opens the door and peers inside . Jo pushes him through the door . The Doctor has failed the test once again , and he now only has two chances left . The entities summon the Second Doctor and Jamie , and inform them of the test and the failure of the other five Doctors . The Doctor talks to the android about the effectiveness of its weapon and its casing , and points out the contradiction of the weapon being able to penetrate anything , and the casing being impenetrable . The Doctor tricks the android into testing it , by shooting its rifle at its own head . The android ' s head is destroyed and it falls over . The Doctor then cracks the combination lock by hand . He opens the door and looks inside . Jamie pushes him through the door . The Doctor is now down to only one chance . The entities summon the First Doctor and Susan , and inform them of the test and the failure of the other Doctors . The Doctor writes PTO ( please turn over ) on both sides of a piece of paper and gives it to the android , leaving it to turn over the paper forever . The Doctor studies the lock , finding it curious that it ' s a simple combination lock . There ' s no way it could have stumped the other Doctors . Susan figures it ' s because this Doctor is more clever then they are , but the Doctor points out that the other Doctors are his future selves . Susan wonders what ' s behind the door , and thinks it could be something valuable , or maybe the way to the TARDIS , but the Doctor is more concerned with the test , and not making the same mistake as his other selves . He notices Susan ' s odd focus on what is behind the door , and wonders if his future selves had any companion s with them . He cracks the combination lock , while mentioning that the essence of a good magic trick is to distract the victim with one hand , while performing the trick in the other hand . He opens the door , and then quickly springs to one side of the doorway . His hunch about Susan being an imposter is correct , as she had moved to push the Doctor through as he opened the door . However , since he has moved to the side , she passes through the space that the Doctor was just in and falls through the doorway . The Doctor has passed the test . The entities abide by their rules and return all seven Doctors to their respective places and times . The entity who gambled on the Doctor losing complains that seven chances was too many , but the entity who gambled on the Doctor winning points out that the number of chances had been decided by the roll of the Monopoly dice . With the test concluded , the entities have finally determined which of them would go first . However , a new problem quickly appears . One of the entities wants to use the dog game piece , but the other entity disagrees , for that entity wants to use the dog game piece . Continuity . " to be added "