Board Thread:Episode Discussion/@comment-30530552-20180116183349/@comment-34633327-20180116195456

The Vault seems to actually be a Pocket Dimension, one specifically made to house the Relic. If it really is one, that means Ozpin warped the fabric of reality just to hide these things. It also explains why Cinder couldn't find Choice despite having been to the Vault. Opening the Vault is one thing, finding it in the vault is another.