i think the suits have a lot of air trapped in them.

affirmative, dry-suits can be made positively buoyant; also they are not wearing weight belts, which are normal diving equipment.

Correct. The old dry suits are one giant bag. So if you flip upside down, all the air will rush to your feet and you be bottom buoyant. Still amazing control.

Yeah, on the one hand I totally want to do this. On the other, I feel like this is some sort of weird Finnish shamanistic ritual I'd be intruding on if I asked.