Question: What happens if a player picks out of turn? 

Answer: If a player picks out of turn, their hand should be called dead. Here are several scenarios that determine what happens next:

• If the player who picked out of turn has not racked the tile, their hand should be declared dead, and the tile returned to the same place in the wall.
• If the player who picked out of turn put the tile in their rack, their hand should be declared dead, and the should remain in the rack.
• If the player who picked out of turn discarded the tile, their hand should be declared dead and the tile should remain on the table. 
• If the player who picked out of turn discarded the tile and the tile resulted in another player declaring Mah Jongg, the player who picked out of turn pays the winner four times the value of the hand. The other players do not pay. 

Source:  Mah Jongg Made Easy 2024, page 19, #15(h)