Position matters a lot if your goal is immediacy and to avoid survival. The most lethal impact from high falls is usually head first, with the body fully extended and aligned vertically. That kind of fall maximizes velocity and focuses the force of impact on the skull and spine. Done correctly, it can cause instant or near instant death due to massive brain trauma, spine fracture, and destruction of the brainstem. Consciousness would likely be lost before pain even registers.
Feet first, on the other hand, is survivable.....barely, and horrifyingly. It tends to result in shattered legs, pelvis, and spine, but leaves you conscious long enough to suffer internal bleeding, nerve pain, or worse. That's how some people end up alive.
Face forward horizontal falls (belly flops) can be unpredictable.
Surface also matters. Pavement or concrete increases the chance of fatal trauma. Water, roofs, awnings, trees? They reduce lethality and often slow you down. That's why many survival cases happen near bridges, rivers, or buildings with architectural "cushions."
