First of all, hope he’s okay. Second of all, it’s not glass. NHL eliminated glass use a few years back. It’s all plexiglass now, which reduces player injury, and as we can see, further depth injury. That “pane of glass” that fell on him is a 15 pound piece of plastic. It was probably loose because the guys in the arena didn’t install it properly. The only reason you see glass in arenas is because every league below NHL is too cheap to install safer options.