The bends would have killed him in a quick ascent. After rescue, he spent 60 hours in a decompression chamber. At 100 ft., he’s at 43 psig compared to 0 psig at the surface. A lot of nitrogen is dissolved into his blood at that pressure.
Amazing I would say it is a miracle.
I came up with 299 kPa gauge. I can assure you that my calculation was easier. I loathe having to do any calculations in ft-lbs, psi, or BTUs.