Think it has been done over before and yes the excess power is noted, however isn't Max continuous about 24"? Nevertheless the slow airspeed at the power shown would indicate a fair load.
The compass and airframe vibrations are very indicative of engine malfunction of some sort. This could be driven by the high power usage giving the engine cabinet and CHT high readings - then if there is a soft spot in the valve area one could easily have a valve stem get grippy or a valve guide get loose, each of which can recover to be virtually undetectable on a mag check immediately afterwards.
Of course these valve problems can strike any time especially if the valve guides are either overdue for a ream or it wasn't reamed properly before WRT operating in a warm environment.
Or it may have been a magneto breaking down with the plugs on the other side not working too well.
So, yes if he is using a higher than acceptable power, flying along with a it won't happen to me or he hasn't worked it out and is too brain dead to do so attitude, then he deserves what happened, his pax did not.
The totally unacceptable bit here is that he continued in cruise throttle setting for some time after the usual half second allowed to get one's emergency thoughts in order. I found myself with my left hand almost dropped my coffee as I automatically was grabbing for the lever and heart thumping soon as I saw the vibes.
There were plenty of places to land at, particularly, he was stupid in placing himself into a low level auto area and therefore placing himself and pax in jeopardy every time a copse of trees flashed by thus excluding safe sites. That was just not on.
In this case he should have immediately entered a low power descent steering toward a selected site as would have been seen on video, landed and then asked for help and shut down until help arrived. No excuses.
For the sake of any future hapless pax for this pilot and operating company I sincerely hope that the regulatory agencies have done something positive with firstly a number ten boot to their posterior, next sent them back for some reading of the AFM and then some revision of general safety flying procedures with an instructor.
Also of great importance the regulatory airworthiness mob should have on their desk a maintenance defect report of the problem and how it was solved, bet they haven't.
It is a good video to repost for mentoring purposes.