In the beginning of the map, just before the ambush event, you can get stuck between a tree and a trunk. [Edit for precision] The tree and the trunk is against a dirt wall, so you actually get stuck between the tree/trunk and the side of the map.
Here is a screenshot of being stuck, taken from the point of view of the stuck character :
The screenshot is looking toward the back of the map, and the drop toward the event is on the right.