you know, and they encountered some unexpected geology, right?

Well, that's exactly what you want to encounter.

Yeah, I want to hear.

So they encountered some pockets of sand and glacial till, right?

And, uh, when, you know, that was, that was entirely different from the silt.

You wound up with blowouts.

You wound up with pressure blowouts.

The blowout is, oh, so these tunnels are pressurized while they're under construction

to keep the water out, right?

Sure.

Um, and so what happens in a blowout,

let me skip ahead and announce a little bit.

A blowout is when, um, essentially, the air finds a way out of the tunnel into the river bed.

And then it forms a big bubble that like, oh, it's a cliff.

It's a cliff.

Yeah, it goes straight up out of the river and you get like a little geyser, right?

It's a cliff.

Ah, now blowouts are particularly nasty way to get killed.

There's a number of ways to get killed in a blowout if you're sandhawk, right?

The air pressure drops really rapidly.

So you might get the bends.

You get the bends.

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