To paraphrase what you said. I think he knew it was a foul and hoped he got away with it. Let's be honest here, the ref just was not in the right position to make a definitive call.
I think it's just as likely that he hoped the ref would make the call, which is why he gave her time to do so. I don't have a problem with how Yapp reacted here. He should not be expected to referee the match when someone is there to do so. No other athlete, in any other refereed sport is expected to penalize themselves.
That's why when available you have replay. To be honest, at least from many viewers watching. Regardless of the path of the cue ball, it actually looked like a bad hit visually. Just watching from home my wife and I both yelled out that was a bad hit at the same time.
