Orikoru
Tour Winner
He might have delayed playing his own shot but he didn't delay 'play' as a whole, because the other guy was playing instead. Play was still continuing. They weren't both standing around waiting for something.Two comments: first, we can agree to disagree on undue delay. IMO, once the player decided he wished to continue play, he gets the 5.6 penalty and that is how I as referee would rule. Reason is not complicated: it is the player's turn to play yet he failed to proceed while the opponent a) played a stroke into a bunker b) went into that bunker and thinned a stroke into another bunker and c) made their way to the other bunker and then duffed another stroke. All this while it is the other player's turn to play. If that is not undue delay, I don't know what is. IMO, there is no way a player can simply discontinue play when it is his turn, for however many minutes the opponent took for those multiple strokes, and then just jump back into the fray without rule 5.6 implications ("A player must not unreasonably delay play......".)
Second: opponents do not have free rein to agree to play out of turn. While permitted under specific circumstances (6.4a(2) Exception) - to save time - if players agree to play out of turn solely for other reasons, those players have agreed to waive a rule (1.3b(1)). And the permitted agreement must be freshly agreed on every occasion. In the OP, it didn't appear to occur at all. And there is no such thing as 'implicit' agreement to play out of turn.