Board Thread:General Discussion/@comment-43897075-20190923040451/@comment-1292715-20190923200846

@Granaatti Relic of Choice? Don't you mean the Relic of Knowledge?

Anyway, to make it more clear as to why they didn't just leave the Relic in the vault, here's a quote from Uncovered:

"Qrow: Well trust me, I'm not crazy about it either. And without the Spring Maiden here to seal the Relic back in its Vault, it's our best option."

It's because Raven wasn't there to close the vault back up. The maiden powers don't just open the vault they close it too. And they couldn't leave the relic there while the vault was wide open. So they have to secure it in another vault.