Another Time Vault question:
How does the new wording interact with Mindslaver?
Time Vault comes into play tapped.
Time Vault doesn't untap during your untap step.
If you would begin your turn while Time Vault is tapped, you may skip that turn instead. If you do, untap Time Vault.
Tap: Take an extra turn after this one.
Player A has Mindslaver.
Player B has a tappedTime Vault.
Player A activates Mindslaver, passes the turn.
Time Vault triggers.
My guess is that Player B makes the choice regarding Time Vault, because the turn that Player A controls hasn't actually started yet. If they decide to untap it, then the turn is skipped. When Player B gets their next turn (whether a normal turn or through activating Time Vault, or any other means), Player A controls it, because it is B's "next turn" since Mindslaver was activated.
That all makes sense to me, but it's a crazy enough interact that I figure I should get a second opinion on the matter.