O-B,
I guess my crackles got in the way of the story!
What he had actually said to me was, 'On the count of 3, pull the Speed Select Lever back.' He was then going to count '3... 2... 1... Pull'. He would then be ready for the rapid yaw, sideways movement and descent.
Because I pulled it back with no countdown, as I hadn't heard that bit due to the crackling intercom, he was completely wrong-footed, and faced with a 'real' no-notice, engine-off in the hover, an extremely challenging exercise in that ac.
Hence his bon-mot 'F*** me, that one was for real.' It was a remarkably calm response, bearing in mind my actions.