What happens if you place arrows in such a way that the expedition gets 'stuck' before that colours arrows are used up?
i.e: There is only one route in, and the several the other side have all been visited by that colour.
We've just played a (2 player) game and I caused it to happed as I needed to reach the East Siberian Sea. We decided that that expedition (blue) was at an end and continued with red. Yellow had run out of arrows and was already over.
can't you remove arrows?