I am going to be doing Charlie and the Chocolate Factory. For the Nut Room Scene, it would be cool to have Veruca give the illusion of falling into the nut hatch by having her slide down a slide that goes into a trap in the stage. I just looked at a theatre I would like to rent. It does not have a trap. But, it does have an apron that can have the floor removed to become an orchestra pit. Therefore, underneath the stage is space for people to stand up in.

The way the apron stage transforms into the orchestra pit is by removing panels on the stage floor. Anyone have ideas of how I could do this? Could I replace the stage floor panel with a panel that has a door in it? Would that be safe??

I would expect that the slide should go well into the pit to give stage hands the time to stop her and help her get off the slide safely. The easiest thing that comes to mind would be to install the slide from below the stage after the set piece is in place on top. That way the slide can be one piece instead of 2. The slide needs to be secured to the floor of the pit once it is in place. If you can't screw into the floor then put a platform in the pit that you can screw into. The trap door needs to be very secure when closed. perhaps 3 henge's and 4 slide bolts from underneath. Since the stage over the pit comes off in sections, then you just need to replicate one of the sections and put a trap door in it. bolts are typically more secure than screws when building the trap door.