When the nose gear fell fast and dug into the grass, the nose gear was right of the right-MLG's longitudinal axis, thus the plane's nose whipped to the right and eventually back onto the runway with the rear of the plane whipping around the nose; thus the very curved marks in the grass.
From the MLG tire marks as it went back onto the runway I estimate that the plane's tires were moving/sliding 25 degrees off the plane's longitudinal axis !
I'd love to hear what the passengers had to say about the ride.