Thanks! I didn't even know you could use tilemaps like that! Can you explain the loops and the "on key released" event?
That's only an or expression: if playerOne.X is not equal to playerTwo.X or playerOne.Y is not equal to playerTwo.Y there isn't the other player on this position.
Otherwise this position is occupied and you put the old position of PlayerOne and Two as TilePosition back to the instance Variable.