Well, obviously you don't want to hang around very long after its on (or even close to) the ground. IIRC, most of the burning deaths were crew-members in the upper parts of the ship who were either caught in the fire in its first stages or didn't have a way out even after it hit the ground. The lower decks weren't ignited till it hit the ground.

But the point is that "impact" wasn't a common cause of death for those who stayed in the ship until it was near the ground. Even when the lifting gas is being vented fairly rapidly, they tend to comedown at survivable speeds.