While ‘Time Of The Doctor’ answered many questions there is one that still remains. Why did this happen on the 26th of June 2010? The Doctor seems to think there is some significance to this at the end of ‘The Big Bang’.
Why would the date be significant to the Kovarian chapter? Whether the TARDIS was detonated remotely or whether it was done by a brainwashed River Song it appears that the TARDIS was targeted for destruction at this exact point.
We know that this was the date of Amy and Rory’s wedding. What we see after the universe is rebooted in ‘The Big Bang’ is probably the closest we get to the original timeline, before the cracks started to change things (such as remove Amy’s parents).
We know that River Song is the result of this union and that the Kovarian chapter would later use her as an assassin. Why then would they wish to prevent this? The answer could be that they had already learnt about the events of ‘Silence In The Library/Forest of the Dead’.
Recorded history would show that River Song is responsible for saving the 10th Doctor. The Kovarian chapter might know only this when they defected, without knowing anything about the rest of her history.
Possibly the Kovarian chapter could use genetic testing to establish who her parents were and blow up the TARDIS in the hope of not only killing the Doctor but also wiping out the River Song. Without her being born the 10th Doctor would die in the library. This works best if they didn’t expect River Song to be onboard the TARDIS (and thus favours the theory that they destroyed the time machine remotely).
When this failed (and the Kovarian chapter might not know why) they then decide to corrupt the Doctor’s saviour, turning River Song into their assassin. They were still caught within the Destiny Trap and their actions unwittingly created the very person who would save the 10th Doctor.
If there is a an outside ‘pull’ to this location and date it could be that the TARDIS was on its way there in ‘The 11th Hour’. With its engine failing it lands far too early, allowing the Doctor to encounter Amelia.
When the Doctor de-materialises he intends to return after 5 minutes but instead is pulled forward 12 years. When he de-materialises the TARDIS is supposed to just go to the moon and back, not travel in time yet it again jumps forward, this time 2 years. It arrives the day before the date of the explosion.
At the time this was taken to just being an example of the Doctor not being able to hit the date that he is aiming for, just as the 9th Doctor accidentally returned Rose home a year too late.
It would now appear that there was something dragging the TARDIS to that date and that location. The location would appear to be important, as the TARDIS is still able to travel elsewhere. Only when it heads to Leadworth does it fall into the trap.
It could be that the TARDIS never completely escaped its grasp, that it was always being pulled back. When River Song enters the TARDIS to get equipment her nature (coming from a timeline that doesn’t exist yet) might have been too much for the ship to endure and it began to automatically snap back to that date.
If this is correct then once again the Kovarian Chapter are responsible for creating elements that would save the Doctor (encountering Amy and Rory) and thus put him on the path to Trenzalore. Without that pull the 11th Doctor might never have met them.
If there is something exerting an outside influence what was it? Where was it placed and when was it removed? Could similar devices be used to pull a TARDIS off course or even prevent it from leaving a particular date?
It could be that the date is only significant because that is the date that the TARDIS exploded. This could be the equivalent to a fixed point in time, with the TARDIS compelled to go to when it is destined to explode. It can delay the final moment but not prevent it.
There could be another event on this date that makes it significant. If it is pulling the TARDIS off-course the Doctor might have originally been elsewhere, doing something important. Knowing where and when the Doctor was going to be the Church of Silence placed the trap.
With the timeline now changed it could be up to the PCs to step into his shoes and ensure that the day is still saved. This could be related to Trenzalore or the return of the Time Lords, which is why the Kovarian Chapter hoped to erase it.
It could be revealed later that a future incarnation of the Doctor had a hand in picking this date. It could be that the TARDIS was always going to explode at a certain point within its own lifespan. The Doctor just ensured that it was ‘this’ time and place, so that he could control the outcome.
River Song suggests that the ship is being flown remotely. The Doctor is one of the best candidates to do this, especially an older, more experienced Doctor. He might even be flying it using his own TARDIS.
The 11th Doctor also suggests that River is doing something wrong when she is trying to control the TARDIS. She retorts that it was the Doctor who taught her. Since this was a later Doctor it could be that he gave her instructions that would lead her to this date, just as he would give her a sonic screwdriver that would download her memory at the end of her life.
The mysterious voice that River hears just before the TARDIS explodes could belong to this future Doctor. If River Song is brainwashed ‘Silence will fall’ could be a trigger to release her.
All of the above could also be instigated by PCs. A whole adventure could be based around the idea that they are trying to save the Doctor and the TARDIS. Alternatively they might need the exploding TARDIS at his particular date to help defeat an opponent or solve their own problem. Since they don’t want to destroy their own TARDIS they are just making use of a TARDIS that they know was going to explode anyway (hopefully knowing that the Doctor was going to fix everything later).