I must have seen to many thrillers, because from the scene where the guy comes to the hospital and meets the fake doctor (one of the mental patients), I start to think that there is a possibility that he as well might be one. My belief solidifies by the fact that, although he is a newly examined doctor, he does almost nothing that he has been taught, almost like not really being a doctor from day one. Finally in the hall of murderers, one room that he is told to be empty (storage room) in the beginning of the movie, later has an occupant. From there on I am almost totally convinced that he is the murderer.

the tranny says "ive got something for you' then licks the window

..The psychiatric intern Clark Stevens (Joshua Leonanrd) comes to Cunningham Hall, a mental healthy facility administrated by Dr. Franks (Lance Henriksen), for a training period before his graduation in medical college. He gets close to the resident Sara (Jordan Ladd) and to Ben London, a dangerous patient lodged in cell 44 in the basement of the clinic. Clark becomes intrigued with a boy, who seems to be a ghost, and finds that Dr. Franks does not use real medication in the patients. A further investigation shows hidden dark secrets in the clinic.. IMDb..

(when i thought i had figured out what was going on, i got mad. i thought it would turn out he was really a patient and was imagining it all, which has been so overdone,)