Was this a 737, 727, or other?
It was a Boeing 737-300.
And yeah, up there at 35,000 feet, it's about -40 to -50 degrees. The cold isn't what would kill them, though, the air up there is too thin to breathe. They'd pass out in less than a minute, and eventually suffocate. If they had oxygen, maybe they'd last long enough for hypothermia to kill them instead...although I don't think the emergency oxygen system on an airliner is designed to last more than a few minutes? They don't use bottled oxygen, they use chemical generators that give off O2 from a chemical reaction. Those generators were what caused that Valujet DC-9 to crash into the Everglades several years back; they were carrying a bunch as cargo, some of the generators activated, and the heat they gave off caused a cargo fire.
If they were up there for an hour and a half, and then descended suddenly...yeah, maybe they could be frozen, I guess. That still doesn't explain why the flight crew couldn't get the plane down to a safe altitude, though.
}:-)4