House of horrors. In addition to what others' have observed, there's a trapped scrag being cooked over a fire, while spike shooters shoot explosive boxes (eventually causing them to blow.)
2 ways to get out of the main building:
-through front door (cyan window door)
or -via sewer by making the center elevator go up without you on it, and dive into the 'red' sewer system underneath to exit the building.
Switch under the swimming pool does open the rocket launcher room, but it's on a timer. It opens about 25 seconds after pressing the button, then closes about 25 seconds after that.
Rocket jumping needed to exit and to get the lightning gun. Need to hit bathroom lockers to open the secret door.