You're making a big assumption that people were (or would've been) showered with shattered glass. Personally, I haven't been able to see shattered glass in the photos that I've seen.
I rode numerous times during the few days the Skyliner was open. The large windows seemed to me to be polycarbonate, not glass. They were very thin, and did not ring when tapped. Polycarbonate would make more sense for a large curved area where visibility is not essential. I don't know what the vent windows are, because they are behind the mesh screen. But if a vent window did break, it would fall outside the cabin, because of the mesh screen.
The eyewitness account of the people claiming to be in the first yellow cabin, IIRC, mentioned a window popping out, but nothing about being showered with shattered glass.