At the south-east of the same level, there's a secret area with some sort of endless corridor. If you manage to find the way out, you will arrive in a room with some skeletons, some mummies and a pressure plate. Walking on that pressure plate will turn the launcher off -I think-. (I'm not very sure of that).
Please forgive my english. My first name is really John, but I'm French...
And then there are the people like me who will NEVER fully understand what exactly goes on in Level 1 of CSB, no matter how many hours I look at it in CSBuild...