Ke iho mai nei ko luna - S9-E13
Continuity mistake: McGarett is going to free dive to Neptune 1 to take some scuba tanks to the crew below. We see him get in the water, and there is one tank ready to be passed to him. In the next shot he is being given the tanks, only now there are two. (00:37:10)
Ke iho mai nei ko luna - S9-E13
Factual error: Full aluminum scuba tanks are 1.5 pounds negatively buoyant when full of breathing air. Two of them would be 3 pounds negative. Yet McGarrett is using them to propel him down to 127 meters as if they were very heavy weights. (00:37:25)
Ke iho mai nei ko luna - S9-E13
Factual error: Three divers arrive at Neptune 1 submarine station where they test the atmosphere at 3% oxygen, 80% helium, 17% nitrogen. Breathing that much helium would make their voices quite high pitched. But their speech is normal. (00:14:30)
Ke iho mai nei ko luna - S9-E13
Factual error: A Neptune 1 dweller is suffering from a panic attack. One of the Five-O members asks if they have any oxygen. Using pure oxygen at that depth could be fatal. At 14 atmospheres of pressure - the pressure of Neptune 1 - pure oxygen would definitely cause oxygen toxicity. Oxygen toxicity is a concern for scuba divers who dive beyond recreational depth limits, use gas blends such as enriched air nitrox, or use 100% oxygen as a decompression gas. Pulmonary oxygen toxicity causes a burning sensation in the trachea, coughing, shortness of breath, and eventually lung failure. (00:14:45)
Ke iho mai nei ko luna - S9-E13
Other mistake: A Five-0 member makes an atmosphere check of the Neptune 1 air. It shows 0.7% oxygen, 80% helium, and 16% nitrogen. A previous check had shown these were the only gases present. So what happened to the other 2.3% of the air? Helium and Nitrogen should have been proportionately higher so as to add up to 100%. (00:29:45)
Chosen answer: They are Junior's SEAL buddies.