Theory:Doctor Who television discontinuity and plot holes/Arc of Infinity


 * TV: The Invasion of Time indicated that the Fourth Doctor's memory of his tenure as President was wiped after he used the Demat Gun to defeat the Sontarans. Yet in this and later stories, the Doctor has full memory of these events.
 * The extent to which the Doctor's memory is wiped, and whether or not it is permanent, is not made clear in that story.


 * The Doctor knows and uses the President's special security clearance code, obviously entrusted to him during his brief term in office. Wouldn't this code be changed each time a new president is inaugurated?
 * Evidently not. There is no reason to assume that it would be changed.
 * Even if it is changed, it's possible that former Presidents retain some of the privileges of office.


 * What exactly is the point of Maxil shooting the Doctor with his gun at the part one cliffhanger?
 * Maxil has a violent streak, and would likely seize the opportunity to fire on him for any excuse.
 * The Doctor and Nyssa overpowered the last guard who held them at gunpoint. Presumably the intention was to incapacitate him to prevent a repeat before reinforcements arrived.


 * How does the Doctor know the creature is an Ergon? There were no Ergons present with Omega when the Doctor previously met him.