Did the glass actually break (I can't tell from the pics)?
I have never actually heard or known of a real person that got injured because of a bulb exploding. I have used large wattage HIDs for about 15 years now without incident.
the outer shell didnt break but several pieces inside did, theres alot of debris inside the bulbs glass, aswell as a white, blueish grey burn the full length of the bulb.
i know its not the end of the world but like alot of us in this hobby fire is always on my mind and a 600 watt bulb doing this gives me the creeps.
I have had a couple do that. Sometimes if you go days on end when a grow is dialed you might not even know it burnt out for long periods. Lights still fire up as normal, just put off small % of lumens. No harm.