Superposition: a Lexicon game
The most remarkable thing about the discovery of a hollow Phobos was that, for once, the government could not cover it up. Once the satellite had crashed upon the Arean surface, all pretense of the hidden world above our heads was stripped from us.
That Phobos was travelling at a velocity concomitant to a body with the same assumed mass of a solid body demonstrates that either the gravity beacons within it were colossal, or the moon itself contained engines; sadly the debris does not allow one to reach a conclusion either way. Since no energy signature was ever detected (not that anyone knew to look), we are left with speculation and detective work to determine how this was done.
Of course, this all points to an extremely sophisticated deception on the part of those responsible, but does not explain why. Theories abound, such as Phobos being an alien base, or a staging post for the visitors, or many other crackpot theories, but for varying reasons, none seem plausible. The coincidence of the fall and the Event is too great to be ignored, but to suggest that one caused the other sadly lacks any form of credible evidence.