Hopefully, you will not ever have to experience being in an elevator that is falling uncontrollably to the ground. If the elevator is only on a few floors from the bottom, then this experience is not life-threatening, but if the elevator is located many floors up, the damage to the human bodies inside the elevator when it comes crashing down to the ground could cause fatal injuries.
Many people believe that jumping up in the air before right before the elevator hits the ground is the best method. The logic and reasoning behind this idea is that the person will be up in the air during the impact. However, when the body comes down, it will be coming down to the elevator floor at the same speed as the elevator was. So, this would not help.