[jhein]

Just for the sake of argument... When they were bracing for impact, they both instinctively pulled themselves back away as far as they could from the impending source. That increased their distance from what they would hit, the dash, windshield or steering wheel. That increased distance gives time for acceleration and increased energy (e=1/2 mv^2). So you'd actually be better off curling into a ball and pressing yourself against the dash or steering wheel than pulling back. Kind of like the posture they advise in a plane crash.