Oracle's Vault

If you cast a card “without paying its mana cost,” you can't choose to cast it for any alternative costs, such as emerge costs. You can, however, pay additional costs. If the card has any mandatory additional costs, such as that of Tormenting Voice, those must be paid to cast the card.

If you don't play the card, it will remain exiled.

Playing a card exiled with Oracle's Vault follows the normal timing rules for playing that card. For example, if the card is a creature card, you can cast that card only during your main phase while the stack is empty.

The cards exiled by Oracle's Vault are exiled face up.