When the crew goes "topside" to search for diving gear, they are walking around the barracks and officers' club. The ruins should be freshly destroyed, having just fallen months earlier. Instead, vines cover the ruins, and in places, full grown trees are growing inside buildings.
Some of the Filipino resistance can be seen armed with M3 Grease Guns. These weapons were not available in the Pacific theater in 1942, barely being into production by that time. certainly not in the hands of occupied resistance personnel.