The Satan Pit ( TV story ) The Satan Pit was the ninth episode of the second series of " Doctor Who " . It introduced the presence of the Beast , a demon claiming to be the ultimate evil : Satan . The Beast would indirectly have an impact on the spin - off series " Torchwood " . Moreover , it set forth an ominous prediction for Rose Tyler ' s fate . The prequel to this episode , " Tardisode 9 " , reveals more victims have been killed due to the possessive influence of the Beast , increasing the body count of this conflict . Synopsis . The Tenth Doctor faces off against an enemy that defies all his beliefs . Rose and what ' s left of the crew are trying to escape from the Beast ' s legion of possessed Ood . Can the Doctor stop an impossible enemy from escaping its prison , and save the universe ? Plot . The three Ood advance towards Jefferson , his guard and Rose . Jefferson gives the order to open fire on the Ood , killing them . In the control room , Zack announces that the planet ' s orbit is stabilising around the black hole again . Danny reaches the others , warning them that the rest of the Ood are on their way . The pursuing Ood kill the female guard with a translation sphere before Jefferson opens fire again . Zack finds himself trapped in the control room , as Jefferson reports that he is low on ammunition . Zack himself only has a bolt gun with a single bolt left . Jefferson recommends " Strategy 9 " ; Zack agrees , and tells him to get everyone together . To Rose ' s relief , the Tenth Doctor and Ida manage to contact the base . The Doctor reports that the seal on the mysterious door is open , but nothing seems to have come out of the pit , which appears bottomless . Zack orders Ida and the Doctor back up because of Strategy 9 , but Ida is reluctant and asks the Doctor what he thinks . The Doctor muses about the curiosity he and human s feel about going down into the pit , but notes that the Beast said he was " the temptation " — perhaps that curiosity is what the Beast is relying on . The Doctor suggests they retreat . Jefferson cocks his rifle on Toby , but Rose stops him from killing the now normal - looking and terrified archaeologist . Whatever it was possessing him , they saw it pass from Toby to the Ood . Toby cannot remember much of what happened , but believes it was the Devil . Down below , Ida explains that Strategy 9 is to throw open the airlock s while everyone else is safe in lockdown ; the Ood will be sucked out into the vacuum . However , as they prepare to be brought up in the lift , the power fails . The Beast , speaking through the Ood , takes control of the viewscreens . To the Doctor ' s question as to which Devil he is , given that there are so many religion s , the voice answers that he is all of them . The Beast explains that the Disciples of the Light defeated him and chained him in the pit for eternity , before the creation of this universe . The Doctor retorts that this is impossible , but the Beast tells them that they know nothing . He begins to speak to each of them in turn , playing on their secrets and hidden fears and insecurities : to the Doctor , he refers to the Time War , calling him the " killer of his own kind " , and ominously predicts that Rose will soon die in battle . The human s begin to panic . The Doctor tries to calm them by reminding the group of the strengths of the human race , demonstrated by their defiance of conventional belief in even making it to this impossible planet , and pointing out that they are united while the Beast is alone . As if in response , the lift cable snaps , and the Doctor and Ida barely get away before its ten miles of length collapses on top of the capsule , severing communications . They are stuck down there , with just fifty - five minutes of air left . Ida decides to rig up the loose cable so she can explore the pit , but the Doctor tells her that he will go down , not her . With the power loss , Zack is unable to implement Strategy 9 . Meanwhile , the Ood are trying to break through the sealed doors to reach the humans . Rose rallies them , getting them to think of a way out . Zack reroutes energy from the rocket to restore half power . Danny comes up with a way to disable the Ood : broadcasting a telepathic flare that will reduce their telepathic field to zero , disrupting their brains . However , this can only be done from the central monitor in Ood Habitation . The only access from where they are is through the airless maintenance shafts below the base , but Zack can extend the oxygen field to follow them through the tunnels . Danny creates and stores the flare programme on a memory card and they scramble down into the tunnels just as the Ood break through the door . Zack directs them towards their goal , aerating each section and decompressing the previous one before they can go through . However , the Ood are also in pursuit . Jefferson stays behind to hold them off , but is too slow in reaching a junction before it is sealed . Knowing that there is nothing Zack can do to prevent his death , Jefferson requests that the oxygen be removed quickly so he can die before he is killed by the Ood . Zack does this , and Jefferson ' s life signs wink out on the monitor . However , the humans have little time to grieve , as the next section is also filled with Ood , and the others have to scramble up into the corridor above . The Ood almost reach Toby , but suddenly his eyes turn red , like when he was possessed by the Beast before . He places his finger on his lips signalling the Ood not to attack him or reveal his secret . The Ood pause , allowing Toby to be rescued by Rose and Danny , who did not notice the momentary change . As the others reach Ood Habitation , the Ood break through into the control room , and Zack holds the bolt gun on them . At the last moment , Danny manages to activate the flare ; the telepathic field drops to " Basic Zero " , and the Ood grab their heads and collapse . Zack joins them back at the mine shaft . Meanwhile , the Doctor continues his journey into the darkness of the pit . He tells Ida how the Devil crops up on so many planets in so many religions — perhaps that is what the Devil is , in the end : just an idea . The line finally runs out , with still no bottom in sight . Preferring exploration to waiting for death , he decides to detach the cable and fall the rest of the way , despite Ida ' s pleas that she does not want to die alone . Reassuring her , the Doctor falls and vanishes into the shadows just as the others regain communications with Ida . Rose is grief - stricken when Ida tells them that the Doctor has fallen . Zack tells Ida that there is no way to get to her , and Ida understands . All they can do is abandon the base and make sure no one comes back here . Rose wants to stay as well , but Zack renders her unconscious and carries her along ; he has lost too many people . They make their way to the rocket past the bodies of the Ood , which are beginning to stir , their telepathic field reasserting itself . Down below , the Doctor awakens . The faceplate of his helmet is smashed , but he discovers that he can still breathe ; an air cushion must have supported his fall . Rose regains consciousness just as the rocket begins to launch . Despite her protests , and even when she threatens Zack with his bolt gun , Zack tells her that it is too late to turn back . Toby seems unusually amused that they have escaped , and when Rose begins to question the relative ease with which they managed to escape the planet , given the various ways the Beast could have killed them , he reprimands her questions with uncharacteristic viciousness . The Doctor finds ancient drawings on the walls depicting the story of a battle against the Beast , its defeat and subsequent imprisonment . The drawings also depict two double - handed jars , which are standing on separate pedestals some distance apart in front of him . He touches them and they light up , illuminating a section of the cave . The Doctor comes face to face with a gigantic demon chained to the cavern wall , complete with caprine head and humanoid body . The Beast who previously communicated with the Doctor was intelligent and vocal , but the creature now towering before him appears to be little more than animalistic in nature . The Doctor deduce s that what he is seeing is only the physical form — the mind , the idea of the Devil , has departed . The Doctor also realises , piecing it together from various clues , that the planet was the perfect prison : if the Beast had ever freed itself , the gravity field keeping the planet balanced would collapse , and the planet would fall into the black hole . The air was not provided by the Beast , but its jailers , so the Doctor could stop its escape by destroying the prison and thus the planet . However , the Beast had prepared for this . The loss of the gravity field would also mean the rocket would fall into the black hole , sacrificing Rose . However , the Doctor tells the Beast ' s body that the Beast ' s plan implies that Rose is a victim . The Doctor adds that he has seen a lot of the universe , and various beings calling themselves gods , but out of all that , if there is one thing he believes in , it is her . With that , he smashes the jars , causing the gravity field to collapse . The rocket shakes , turns and begins to be dragged into the black hole along with the planet . The body of the Beast writhes , flames bursting from its skin . On the rocket , the runes appear across Toby ' s skin as the Beast takes full possession of him . He breathes fire and angrily defies death , ranting that " nothing will ever destroy me " . Rose grabs Zack ' s bolt gun and aims it at the cockpit ' s front window . Saying , " Go to Hell , " she fires , shooting out the glass . As the air rushes outward , she unbuckles Toby , who is immediately blown into space towards the black hole ( into nothingness ) . Zack raises the emergency shield , but they are still falling towards the black hole . In the base , as the planet now hurtles towards the black hole , the Ood , now free from the Beast ' s control , huddle together nervously . Near the pit , Ida slowly falls to the ground , the last of her oxygen exhausted . As he stumbles away from the Beast ' s burning body , the Doctor finds the TARDIS in the collapsing cavern . The rocket crew watches the planet vanish , and brace themselves for death . Suddenly , everything becomes still , and to Zack ' s amazement , the rocket turns and heads away from the black hole . To Rose ' s delight , the Doctor ' s voice comes over the speakers , telling them that the TARDIS is towing them away . The Doctor was also able to pick up Ida — who would be fine aside from a little oxygen starvation — but unfortunately had no time to save the Ood . The Doctor and Rose are joyfully reunited in the TARDIS once the rocket reaches clear space . Back on the rocket , Rose asks the Doctor what the Beast really was , and the Doctor replies that whatever it was , they beat it , which for him is enough . He assures Rose that when the Beast said she would die in battle , he lied . Before the TARDIS dematerialises , Ida asks who they are , and the Doctor tells her , " The stuff of legend . " Heading back to Earth , Zack dictates the final report of Sanctuary Base 6 , recording the names of those who died with honours , beginning with Toby and continuing with every Ood that served on Sanctuary Base . Story notes . Filming locations . " to be added "