The relevant Wikipedia article (with lots of authoritative sources cited) is Space Exposure:
A rough estimate is that a human will have about 90 seconds to be
recompressed, after which death may be unavoidable. The low pressure
outside the body causing rapid de-oxygenation of the blood (hypoxia)
is the primary reason for unconsciousness within 14 seconds. In 1965
Jim LeBlanc lost consciousness after approx 15 seconds of being
So it is realistic for Ryan to survive exposure to space for the depicted time, which is certainly less than 90 seconds. However, if the time without atmosphere lasted more than 15 seconds (which I am not sure it did from memory - 15 seconds is actually pretty long), she should have lost consciousness from the lack of oxygen.
Temperature would in fact have been pretty irrelevant - space is extremely cold, but there is nothing to lose heat to except via radiation, which is comparatively slow (and would not occur inside a previously heated capsule).
However, the scene also depicts uncontrolled decompression, which is very dangerous on its own:
Explosive decompression occurs at a rate swifter than that at which
air can escape from the lungs, typically in less than 0.1 to 0.5
seconds. The risk of lung trauma is very high, as is the danger
from any unsecured objects that can become projectiles because of the
explosive force, which may be likened to a bomb detonation.
So the question is: did opening that hatch cause the air to leave the capsule in less than 0.1 to 0.5 seconds? That's way too short to time from the video. It may be possible to calculate. My intuition says that the hatch is pretty big compared to the size of the capsule, so that decompression would probably happen quickly enough to cause lethal lung trauma.