was the nurse evil did she keep him in the nut house to help him ?

Rating: 10/10 (9 November 2005)

Hi I have seen this movie 3 times now and watched it again last night after not seeing it for a good year or so.
it has to be 1 of the most powerful movies I have ever seen. I am a average 25 typical male but the ending does something to me which is hard to explain were I have to remind my self "this is just a movie" but really it is more than that ! to get to my ?. I cant make sense of the nurse in the movie. when Murphy is due for realise and the 3 doctors are in the room with the nurse and they all decide that he is sain and should be released.
and she then she gives the story of that we shouldn't pass on are problems to other people etc.
why is she doing this ?? is she doing it as she wants to help Murphy or in short words because she is pure evil and wants to undermine him ???