User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-5577244-20121222052302/@comment-5577244-20121222055438

The  door may not be a physical door. Things in prophecies are not always ment to be taken litterally. The door may be some sort of portal (DOORWAY) to Tarturus. I highly doubt it being a normal door seeing as how Tarturus is WAAAAAY down under the surface of the earth. Destroying the surface side of the portal may be enough to stop things from comng through.