It would be interesting to see the same test with various types of rock such as lime and sandstone on canyoneering helmets.
Brain bucket is a good idea, also I would mention wearing proper footwear is also a good idea. Imagine that hitting your toes. Brandon Sent from my SM-G955U using Tapatalk
A few weeks ago I count myself very fortunate to have been part of a near-miss with a falling rock (~150 pounder) while on rope. I can certainly empathize with this young man's involuntary reactions. (Along with adrenalin being a chatty drug, it can also whip up immediate nausea.) When this one unknowingly dislodge (60' up) I was only showered by debris, as it ricocheted off the wall, landing 5' from the rope. Who knows if the helmet would have prevented serious injury. At the very least it would have protected my stylish helmet-hair.