After Miss Juliet's death the doctor exits the nurse's room, which connects to Miss Juliet's room, via a door swinging outward (inward to Miss Juliet's room). He listens in on the nurse and detective's conversation who are in the nurse's room, then closes that door which is now swinging outward. When the detective starts to enter Miss Juliet's room he goes to enter the door inward (toward Miss Juliet's room) then the scene cuts to him entering Miss Juliet's room via a now outward swinging (inward towards the nurse's room) door.
Inspector Patten shoots at a door lock twice, then kicks in the door, but in the next shot, there is no visible damage to the door whatsoever.
Dr. Stewart tells the nurse to "prepare a hypo, amyl nitrate, one tablet". Amyl nitrate only comes in liquid form. Further, injections are not prepared from tablets. He repeats this same error later.