5g forces on impact would imply the projectile stopped at ~50m/s^2 (numerically 5x the gravitational constant) deceleration. In a free fall, it hardly exceeds 1g, unless the aircraft was powering it to hurtle down faster
Yes, it did. Now what does it tell you that the crew never lost consciousness?
G-forces are not experienced equally based on the axis on which the plane is moving or the speed at which it accelerates/decelerates. The airframe of that plane was deformed with the wings bent permanently indicating non-plastic deformation, and yet the passengers were fine.
Imagine a plane rotating on the axis through the COG nose moving 'down', that would give the pilots negative G, the people near the tail positive G and everybody in between something along a gradient, those near the COG would likely not experience much difference. If the plane came out of a steep dive then there would be a lot of positive G, and if someone were to black out that would likely be only for a moment. A powered descent into terrain would be far less in terms of G's than violent maneuvers such as steep banks or coming out of a steep dive.