iOS while循环将索引恢复为零

I have a game with a board with 26 tiles. The player rolls a number between 1 and 12, and the player then moves that many tiles. I do this by having an array (indexes 0-25) of the tiles, in order. This is my way of moving the player across the tiles (this contains code from Sprite Kit, which I know is under NDA, but the question isn't about that)I have a game with a board with 26 tiles. The p