The swamp is considered impassable, so not a single frontier guard comes here, just like the locals, but border guard dogs can hear loud sounds. It is important to move strictly along the route marked with light ribbons. In this case, after five days you can be on the other side of the border. It is better to cross the border in a group, it is more likely to get alive.
Fog is the curse of these places. It appears suddenly, and becomes so impenetrable that it is impossible to tell what is in two steps in front. In a fog you need to move slowly and be extremely cautious, so as not to take the wrong turn. Test the ground before each step, try to tread exactly in footsteps, otherwise the losing a group member probability is very high.