Durafly Auto-G2 Gyrocopter death spiral crash at Wavemasters

This RC Hobby King auto gyro took a hit at Wave Masters near Hollister California

[Elephantine]

Your rotor slows down to almost zero RPM at 1:20. *You must keep that rotor RPMs up or autogyros fall out of the sky.*

[ChikzDigit]

Had you turned back on the auto rotate it would have been recoverable

[claywedgemore]

So, what caused the giro to spin in? Was the forward speed too slow to keep the rotor spinning fast enough ? These things are fascinating, . Some say they are docile and easy to fly, but this vid shows different characteristics!I have heard of the deathspiral and that it is topical of autogiro behavior. Experienced pilot please explain!