Continuity mistake: When Skinner walks into the cafe (the time he gets shot) another man is just walking out, leaving a table with a used glass and coffee cup. The waitress is in the back, getting Skinner a cup of coffee (she couldn't have cleaned the other table yet), but when we look over Skinner's shoulder you can see that the other table is cleared and has a clean coffee cup (turned upside down) on it.
Factual error: At the beginning of the scene, XO Johanson is looking through the periscope. However, it is nonsense, because the submarine was in silent running, and the Japanese destroyer was circling it, so the sub must have cruised in deep submersion. The water depth there was approx. 270 meters, as the French salvage team claims at the beginning of the episode. There is rarely any significant light beyond 200 meters. Looking through the periscope in these conditions would be completely useless.