Jack In The Box - black art model –
I can tell your a fan of the art. Magic illusions have very little place in a haunted house. That being said (too often) you have to let go of the illusions you see on TV. At best you will need to re-design illusions to work in your haunt. Once you do this you can create your own from the effect (the results) on up. In other words it would be like writing a mystery, you begin from the end and work you way to the beginning. This will help you with the way the illusion should look and function.
I would suggest not having people come back to the same room again. You can slow them down if you need to though. The concept your looking for I am assuming, is a lightening fast change (metamorphosis). This is very easy to do and even easier inside a haunt. A person can change into another person at the blink of an eye. For example, if a man standing in front of you suddenly changes into a grotesque zombie, that would be the effect. How it could be done is the man has two half costumes. Looking directly at him, he looks normal. On his back is the zombie costume including a fake head. He would only need to turn around to shock you. Before you want to add special lighting to this, try it first in your haunt you might be surprised at how simple this is. Another way to pull this off is having a costume change. Not the expensive ones that you find on stage but a simple half-costume from head to toe. Have your actor dress in full zombie costume then put over it this 'regular guy' costume. When you need a change it (the regular guy costume) is pulled away.
These are easy solutions but there are many, almost countless ways to make your illusions work. If you would like something more technical shoot me an email. But for now, Having 2 actors in a room where one is being tortured while the other is doing the torturing is all you need. Try the costume change while laying down. I would like to know how that turns out for you.