[Clipper]

So the question is that player D wants to use the GDO to discard A's card and player B wants to play a Room instead. I understand that GDO requires discards, so the order of play will be determined by which action happens first: either B's Room hitting the table or the discards for GDO hitting the table. B should really wait until A has read the card for fairness, though, given that the two players are essentially racing. Player D cannot wait around to see what his opponents are doing, such as playing Wandering Monsters before making up his mind to use the GDO to discard anything except the most recent monster.