It pauses the interpreter, I believe. As the interpreter would update, it would check the variable and wait, although, due to the fact that it is an instance variable, in no possible way could it work. However:
You can find a great deal of the eventing commands hidden in the "Interpreter" sections of your Script Editor.
So, you could, in essence, find the method for waiting, and be finished with it. Also, there's a chance it could be #Interpreter->wait_frames or such. Then the other idea is possible.
Hope I've been helpful!