10 Doctor Who Problems That Time Travel Would Have Solved

2. Prevent Marcus's Discovery

Pyramids of Mars is one of the most iconic Fourth Doctor serials, with Tom Baker and Elizabeth Sladen in top form as The Doctor and Sarah-Jane Smith respectively. Gabriel Woolf appears as Sutekh, the extraterrestrial who served as the inspiration for the Egyptian God Set and who would later return as the voice of The Beast in The Impossible Planet and The Satan Pit.

When Professor Marcus Scarman discovers and accidentally opens Sutekh's prison, a nailbiting race follows to stop the evil alien from carrying out his plan. The Doctor impresses on Sarah-Jane the need to stop him, as with a trip to the future he is able to let her see the devastation that will come from its reign.

Therein lies the reason it is included here. The Doctor used the TARDIS to travel to a possible future so what stopped him from travelling to the past, a past where he managed to stop Sutekh from rising at all? Though he is able to cause the creature to age to death using a time tunnel, it still comes after several people have paid the price for Scarman's curiosity.