I know... I'd want us outside as well, if we use the Hallow spell.  The thing is, if the lever needed for plan A has been destroyed, then we'll make our way outside again, and begin immediately on finishing plan B, but Casting the ritual Hallow, as the other priests finish the Positive Energy Merger.  That way, during the 4 hours the rest of the major ritual will take, the Hallow effect will help us contain the Undead.