Tickets for the interactive theatre company's last show are almost impossible to score, though if you get one there's a chance you'll have your mind blown. But what exactly is it? The creators reveal what they can The secrecy agreement signed on arrival means I can't tell you about the part of the show where [redacted] is [redacted] on my [redacted]. Nor can I fully describe the flummoxing moment when I'm asked to [r…