Quote Originally Posted by Knives122
And what was the point of showing the Commander lean over his balcony and look down at a light over the water(which was gold colored) if the gold was in a corner?
Judging from how the commander phrased his trap and the last scene of the crab climbing up the rocky shore, my guess is that there's some sort of high tide or low tide that prevents ships from leaving. So the commander could just be looking at the water level and timing.