Let's say our Sharon deceived us. He said that a doppelganger impostor infiltrated the palace and took his place. That's why he ordered them to dig a tunnel into the palace.
Added 6 minutes later
We could go even further and postmodernly break the fourth wall. Let the characters give a link to this post and say that they decided that the Mage Guild mistakenly created a doppelganger.
Where do we end up when we save the world?