"Beware of the waiting room." He closed the door at once, as if he had rehearsed that moment. I opened it quickly, and leaned out to call after him, "The what?" He turned, but only to give a sharp wave, the Trafalgar Square crowd swallowed him up. I couldn't get the smile on his face out of my mind, it secreted an omission. Something he'd saved up, a mysterious last word. Waiting room. Waiting room. Waiting room. It went round in my head all that evening."