No it is not detonating or trying to hurt itself because your were running most of the hill at wide open throttle.  In the other video it sounded like you were running the engine at high RPM but at about 1/4 throttle opening and running very lean. 

Coasting down the hill with the clutch pulled in, is hard on the throw out bearing and clutch plates. 

Guys think that they are cooling there engine by coasting down the hill with the engine idling.  The water pump is not pumping much water at an idle.   You  are primarily cooling the water that is in the radiator but not taking much heat out of the engine to put into cool radiator.  You have to move alot of water through the engine to move the heat into the radiator.