User blog comment:Blue Sky/Mordred and Cerdan/@comment-4650675-20111221210249/@comment-5036924-20111222095744

Unless they believed Mordred was special and needed to survive? In kind of the same way unrelated people sacrifice themselves for Arthur and Merlin - to keep a destiny intact.

I do see that they obviously cared for one another, but somehow I think Mordred's actual parentage would be too important for it to be just a throwaway thing in a character who didn't survive the episode. Who knows, though, the writers may just chuck something else in later like they did with the Uther thing.