The main danger of the HALO jump is the risk of hypoxia, which is when oxygen levels in the blood are lower than normal. In a behind-the-scenes video, one of the stunt performers, Ray Armstrong, explains that at such high altitudes, “You start losing your mind, but you don’t realize it. You’re not getting the oxygen to your brain, so you’re making what you think are sound decisions, and they’re not.” Therefore, the actors needed a constant flow of oxygen. That’s where the special prop came in.
Action props supervisor Toby Shears says they had to turn the helmets into an “oxygen delivery system” while also shining a light on the actors’ faces since the skydivers usually wear black, obscuring headgear. The audience needed to see Tom Cruise’s expressions during the intense free fall while he’s saving August Walker (Henry Cavill) after Walker is struck by lightning. The team ended up using LED strip lighting so any spark wouldn’t set the actors on fire. Taking extra measures for safety, Tom Cruise says the helmet was “rated with the Royal Airforce. They took it to a hyperbaric chamber just to test it,” and Armstrong confirms it was tested “until it was deemed beyond its safe working height.”
The HALO jump in “Mission: Impossible — Fallout” is a stunning sequence that demonstrates the filmmakers’ dedication to realism and high-stakes action. The story of this small but significant prop — a helmet which allows actors to breathe while performing one of the most intense stunts ever — reminds us just how much dedication and care the filmmakers put into the adrenaline-pumping set pieces that make the series so beloved.