Here goes stupid question. How did the Gravemind get to the Citadel after Arbiter killed the Prophet? The tentacles seem to come up from below and the sides of the Citadel but as we know, there's nothing but a huge chasm that probably drops to the other side of the Installation into space. So, somehow the Gravemind made its way from the crashed High Charity "over" the void that lies beneath the Citadel. We never see the rest of its body during this scene or when you're fighting your way out of the Citadel. Just its tentacles. Maybe someone can explain this? Like I said.... Odd and dumb question. :P