The biggest problem with the pilot (besides she can't lower the collective) is she is overriding the governor! I dont think she overpitched.
I think she got spun around, and in her fright, put a death grip on the throttle. Then when she stomps in the pedal, and/or raised collective the gov can't increase power.
This is pretty evident to me because she is overriding it all the way down to the bottom. Even after she "recovers" and it flying along at the bottom, the horn goes off again. There is no way this could happen unless she was severely overpitching, (which I dont think is the case as she is flying along at the bottom)....or she I holding the grip so hard the gov cant roll the throttle up.
I have had several students do this. They get nervous and tense up on the throttle. For those used to flying turbines, the Robbie throttle continually moves by governor actuation. If you tense up on it, you will simply not allow the governor to work.
Just my .02...