User blog comment:Morganaforever/Episode Review: A Lesson in Vengeance/@comment-5674726-20121118003429

Morgana really needs to learn that shooting is not too good for her enemies. Forget prolonging the agony, all that matters is that you get the job done. Had she gone for quick and deadly rather than slow and painful when it came to picking her poison, Merlin wouldn't have had the time to heal Arthur.

''Morgana is without a doubt a very smart woman, which is why it has made me wonder why she chose to come to Camelot as an old woman (aka Hilda) again. She looked very similar to how she had looked before, so someone would definitely have recognized her. So why would she possibly risk of getting caught?''

The first time, she interacted with people inside the palace so she probably took a calculated risk by using the ageing spell again. If one of the knights saw her, she's more than a match for one of them. If she has no other means of magical disguise at her disposal, it'd be the best option available to her if she has to meet with Guinevere inside the walls of the city.