The point here to note is that, a player waiting for either an in-between tile, edge tile (an eight and a nine, waiting for a seven) or a single tile to complete the required pair can only claim a 'Sequence Hand' if he Self-Pick (自摸 "zì-mō") that particular tile. If he is waiting for any two tiles (a two and a three, waiting for either a one or a four) to complete the winning hand, he can claim these tiles from any party who discards it.