User blog comment:Ḡwẵine Ḹٍٍkƨ Ĺiĸe Ͼềлȑềd/WORST plot hole in the HISTORY of 'Merlin'/@comment-4916403-20121014212601/@comment-4190137-20121017214729

I remember that Gwen was there - just check out that scene and you will see her. ;)

And Mordred had an angry expression. I guess we'll never know what truly happened, but to me that indicated that Gwen saw Mordred use magic.