im not excusing the broken glass, but as far as the legal implications, i bet the zuffa contract covers all medical costs and also mitigates minor injuries like that. it would be insane to run a training camp like the TUF gyms without a clause that mitigates minor skin injuries at the very least. cuts like that can happen easily during standard training. TUF i'm sure covers all bills and I can't see zuffa leaving themselves open to litigation over little cuts in their contract language.
so while it doesn't make what Junie did ok, it certainly makes Zuffa's position better than had he cut some random in a bar. just pointing what could be a relevant difference legally speaking.
If you are looking at it from a position of Dana's integrity... don't. He is there to make money and produce the best fighter possible, thats it.
His helmet was stifling, it narrowed his vision. And he must see far. His shield was heavy. It threw him off balance. And his target is far away.