What a load of tosh
Divers dive in water. Helicopters fly in air. Different density. The pressure in water doubles in 33 feet but the pressure in air takes 5500 metres to drop by half.
Depressurisation in a fixed wing to 8000 feet might be an issue but flying at 500 instead of 2000 feet is just inexcusable. Might even be illegal.
What is important is early pressurisation and we now have portable chambers we can use in helicopters so the diver can be pressurised during transfer.