Doctor Who Season 10: 7 Big Questions After 'Extremis'

5. Why Did The Monks Leave The Veritas To Be Found?

If this was just a practice, like a simulated war game, then it would have been pretty dumb of the Monks to allow their plans to have been written down. But this is far more than a simple test run. The point of the experiment was not to hone their capabilities to take over the world, but to test the human race's ability to defend itself.

They wanted to see if and how the simulants could uncover the truth and what they would do with that information. The knowledge enables the Monks to second guess how the cleverest minds would react when the invasion proper takes place. It tells them who in the real world, if anyone, they need to make special contingency plans for.

They discover that the near universal response to uncovering the truth, from the world’s most powerful priests through to its scientists and politicians is to get the hell out of there. The experiment is the great leveller and leads the Monks to fearing nobody, regardless of beliefs or expertise.

The significance of the Doctor asking Missy for help, is not so much because of his blindness, but because locked away in the quantum fold chamber, she is the only inhabitant on the planet that the Monks know absolutely nothing about. As far as their simulations are concerned Missy doesn't exist. She is the one thing they are completely blind to.