10 Unanswered Doctor Who Mysteries
2. Why Did The Doctor Run Away?
The oldest question of them all and one that all show runners have hinted at without ever giving a definitive answer, the grand old mystery of why the Doctor ran away from Gallifrey remains the show's biggest unanswered question. There have been a few tongue in cheek comments from various incarnations of The Doctor, including one from Tennant's Doctor stating that he was one of the ones who 'ran away', but a concrete explanation has never occurred.
One suspects and fears that current show runner Chris Chibnall is going to try and come up with a definitive answer, which would really be a shame. Recent revelations open up a number of possibilities, not all great, most notably that the Doctor found out some information in relation to him being The Timeless Child and fled because of this.
The query in regards this theory is just how much the Doctor remembers or knows information about The Timeless Child revelation and why they can't remember now. The fact that a 'prior' incarnation of The Doctor as played by Jo Martin had also chosen to flee to Earth makes a link between the two events highly likely.
Some non Timeless Child related theories as to why The Doctor made a hasty exit include Susan's life coming under threat, revelations of the upcoming Time War or The Doctor quite simply being bored of the constrictive life on Gallifrey. Given a choice, most fans would likely choose the last option.