User blog comment:ArthurMerlinLancelot/FINALLY/@comment-5684105-20121216072859/@comment-203.219.62.188-20121217023229

Regardless of whether Morgana knew she was the vessel of the enchantment or not, she knew that she was in some way responsible for what was happening to Camelot and Morgause's attack. And, as has been pointed out, she admits to knowing WHY Merlin had poisoned her. Yes, she would have felt betrayed by Merlin regardless of his reasons because he (a friend) poisoned her. But it doesn't make Merlin responsible. She made her choice. He reacted the only way he knew how.

As for Mordred, Merlin did do wrong by him but he tried his best in the end to protect Arthur and help Mordred at the same time. There wasn't much he could do in that situation. The only other thing I think Merlin could have done is to actually tell Arthur about the prophecy and Mordred's role in it at the time when he was pleading with Arthur to spare Cara. It was either that or allow Mordred and Arthur to fall apart and for the prophecy to be fulfilled. But, unlike Merlin, we could already foresee the result of this episode and, unlike us, Merlin has to deal with the consequences of a bad mistake. So admitting the prophecy might have been too high a risk with so many different consequences.