Merlin: This is what Morgana wanted all along.
Gaius: She couldn't suffer the ignominy of seeing Gwen on her throne. It is indeed a cruel revenge.
Merlin: But it is Morgana who created it. I must make Arthur see that. If he knew that Lancelot was a shade...
Gaius: It wouldn't change what Gwen has done. It's her betrayal that matters to the King, Merlin. Telling him of Lancelot's true nature won't change that. It's Gwen who must pay the price.