Knocked unconscious by a bright flash the Doctor,Ian,Barbara and Susan awaken with mild memory loss to a TARDIS with nothing outside. The water dispenser malfunctions,the viewer is showing seemingly senseless images and doors are opening by themselves. Pretty soon the foursome began to turn on each other in paranoia. First Susan than the Doctor turn on Ian and Barbara whom,being aliens from their point of view with an ambition to return to Earth have sabotaged the TARDIS somehow. Still none of this add up. Despite Barbara's feelings being hurt by the Doctors accusations he and Ian are able to derive that the image on the viewing screen and even their clocks stopping are indications that,following their leaving Skaro the doctor made a mistake and sent them to the beginning of the universe where time itself is forming. And the TARDIS is merely caught in the maelstrom. Once released from this force,the crews confidence in each other is restored.
Being a claustrophobic "bottle" episode,this gives the writers the opportunity to explore the personality of the still very undeveloped Doctor a bit more. The unusual forces of the episode bring to mind different levels of paranoia and fear in each of the characters. There's Ian and Barbara's fear of understanding nothing of what's been happening so far and just muddling through. There's Susan's fear from youth and inexperience,as well as concern for her grandfather. As for the Doctor there seems to be a broader level of anxiety at work. His immediate accusations to Ian and Barbara of sabotaging the TARDIS were early indications of his renegade status among his native people,and his concern at getting caught at anything. The fact that he realizes this about himself seems just as much a motivating factor in finding the real solution to their problem as the problem itself was proving to be. So this is a brief but telling psychological study of the doctors character. And actually had a significant impact on the direction the show would take in the future.