[Question]The nature of the Vengeful Spirit

I think it may have been in Saturnine but Abaddon comments on how the ship has grown on the inside, with him walking through a door that shouldn’t have led to anywhere but outside the vessel. In this room Horus holds his meetings and I remember it also being where he fought the Emperor but after Horus dies, the chaos corruption supposedly leaves yet the room still exists am I getting these rooms mixed up or did ship remain changed ?