First Keith set up a simple scene and let a couple of improvisors play a couple of minutes of it.
Then he takes the improvisors outside the room and give them some trick they can use.
And now the “audience” can see the improvement.
Prepare, always have something when you go on stage, you are the instrument, keep it tuned, vibrant and ready, it´s you that must make something happen and not some mysterious force.
You have to be prepared if you want freedom.