I think they all died pretty quickly because if anyone had survived for long, the bodies of the crew wouldn't have been left where they fell. Do you think the inertial dampners were offline? Do they work if a spaceship crashes in to a planet or are they just for when the spaceship is in space?
Tom states that they're offline in the episode.

Chakotay also states that everyone was killed on impact, though how he could be 100% certain is unclear.