During the filming process, the actors had bruises on their bodies and swellings on their heads to varying degrees. All this was attributed to the perfectionism of filming consultant Patrick Hanniffin, who was "realistic and unscrupulous". Patrick Hanniffin had operated the German Reich submarine. He said that the submarine space at that time was "very small". If the director and producer were determined to simulate the real situation at the time, they should spend a huge amount of money to build a Nazi submarine with a proportional interior, so that the film can be credible. Because these actors are all heads of Malaysia, and the submarine sergeant at the time had strict height requirements to save personal space. The director asked the actors to run quickly in a small and claustrophobic cabin and quickly pass through the narrow gates. With a little hesitation, these tall actors can understand what is meant by "head hitting." There is always water in the bilge, and the director always tells people who are not proficient in action to come back again and again. After a day of filming, the bruises on his body can't lose to the martial arts star. Only Harvey Keto, who plays the master chief, is fast and relaxed. Others thought he was "ginger is old and hot", but he secretly laughed and admitted that he had graduated from the Naval Academy and was well-trained a long time ago.
Hanniffin said that the submarines at that time were not as well-designed as they are today, and they often leaked. So the director obeyed, and led the water pipe to the top of his head. The actors were drenched and fell down one after another because of the slippery ground. Especially when the submarine encountered a burst of mines, the boat shook violently from side to side, and everyone was hit. Dizzy, take turns to perform "dog eat shit".
