The Lost Key 3

It sounded ridiculous when you were told that you would lose the key to the main door if you spent one night in this room. You decided to accept the challenge and went to the rather mysterious room. You locked the door from inside, had you dinner and went to sleep. Next morning you woke up and checked your pocket. You were shocked to discover that the key was not in your pocket and neither was it anywhere around for you to be seen. You will have to think and act smartly to solve all the puzzles and find the lost key in order to escape from the room.