Suruthi

Yes, you do.

Because they breathe in like a mix.

It's not just the air that we breathe in at one atmosphere.

They make a special like tri-mix for them.

And helium is one of the gases that is quite prominent in this mix that they give saturation to hypers when they're down in the bell and the living chambers.

And Hannah's right.

All these big burly men speaking in incredibly high-pitched voices.

And it was on the 5th of November 1983, on the Byford, that a four-man team of saturation divers were based.

At around 4am that morning, the two Brits, Edwin Arthur Coward and Roy P. Lucas, were asleep in one of the chambers.

The two Norwegians who made up the team, Bjorn Bergesen and Troels Helvik, were just coming up in the diving bell after a long shift.

Two tenders, which is the name given to, like, diving assistants, Martin Saunders and William Crammond, were on hand to help.

So Martin and William basically dock the diving bell to the living chambers using a device called a trunk, which is essentially a tunnel.

And the way it's meant to go is that you lock in the trunk, pressurize it to the same atmospheric level as the diving bell and the chamber, which here was nine atmospheres.

And then you open up the doors to make the trunk accessible.

And then you have the divers crawl through the trunk into the living chambers.

That's how it's meant to go.

And then once the divers are in the living chamber, they close the door to the trunk and then it's depressurized.

This is very important.

It's depressurized before the diving belt is detached.

This all has to be done in a very specific order to avoid pressure differences causing an explosion.