Once there lived a king who did not allow anybody to leave the kingdom

Once there lived a king who did not allow anybody to leave the kingdom and any foreigners in his kingdom. There was only one bridge that connected his empire with the outer world. A guard who was a sharpshooter was specially assigned for a lookout on the bridge. According to the orders, anyone moving outside should be killed and anyone coming to his kingdom should be sent back. To take rest, the guard used to sit inside his hut for 5 minutes and return back on the lookout. The bridge took a minimum of 8 minutes to pass.

Even then, a woman was able to escape the kingdom without incurring any kind of harm to the guard.