They suffered explosive decompression, like a baloon when it pops.
Air pressure for breathing was near 14.7 PSI, atsmopheric, possibly lower,
air pressure (not inpact pressure) at 200,000 Ft is somewhat less than 0.5 PSI,
as 60K Ft. is 2 PSI and they were more than 3 times that altitude.
That is approximately a 30:1 expansion factor.
The Challenger when it failed, had the upper cabin remain intact, the lower
compartment was ruptured, and experienced explosive decompression.
The occupants of the Challenger crew cabins upper section were talking
for the 5 minutes it took to fall and hit the ocean.
They may yet find the upper section of the Columbia, there was a report
of an automobile size object falling into a lake or resivoir, possible candidate.
First notice of abnormal readings were over Nothern California: At 8:53 a.m., when the ship was crossing over San Francisco, a data point flickered on monitors at Mission Control indicating that the flow of information recording the temperature of the hydraulic systems in Columbia's left wing had suddenly ceased. At 8:56, when the ship was somewhere over Utah, the temperature in the landing gear and brake lining?again on the left side?registered high. Two minutes later, three temperature sensors embedded in the skin on the left flank of the ship quit transmitting. A minute later, temperature sensors in the left tires winked out too. All these data hiccups were reported by the mission controllers to the flight director.