Check out this video taken from a camera mounted in the vertical stabilizer.
Notice that on the third maneuver, the pilot tightens the bank beyond 90 degrees. As the nose fell through the horizon, a high sink rate developed. At low altitude, he could not recover. He was successful in leveling the wings and getting the nose up enough to allow the tail of the aircraft to strike the water first. That saved him.
High wing loading can degrade turning ability. But these type aircraft are designed for optimal performance. However, by their very design, and at such low altitude, error can be magnified.