While you can finish mist banks, they never trigger scoring (you remove ghosts instead). However, placing the tile can also trigger scoring in the usual manner.
When placing a tile triggers scoring – regardless of whether there was mist on the tile or not – you always have 2 options:
• Either score the points as usual.
• Or remove up to 3 ghosts from exactly 1 tile of your choice, returning them to the supply.
Special case: When a single tile triggers scoring more than once, the active player decides what happens for each scoring separately.
You finish the road. Instead of scoring 4 points, you choose to remove the 3 ghosts from the topmost tile instead