After Magnus broke through the Webway and destroyed the Golden Throne in his attempt to warn the Emperor a war started to prevent demons from flooding through into Earth. In several short stories and descriptions of this part of the Palace a large pair of doors are described, the size of a Titan in front of which stand Custodes and Sisters of Silence in armor that looks like it has been in some great battle, and behind the doorway can be heard a great war taking place.
In addition there are other sources that describe someone seeing injured centurions as if they have fought in a great war.
Has it ever been described how these Loyalist soldiers were transported to and from the battle front, were the giant doors opened to allow forces in and out or did they get there some other means (teleport etc) or did the forces, once inside the battle, never get out?