That's nasty, Sedate, glad you're not hurt- or homeless. I've been there, and it's no damn fun at all- in my case, the house fire was deliberately set, nothing to do with a grow op.
Definitely a serious mercury cleanup HAZMAT issue. I wouldn't smoke anything coming from that room until it's fully cleaned up. That includes the crop currently in there, no way to clean it up, just have to toss the batch...
I think the glass envelope shattered, leaving the element exposed and in close proximity to your MDF reflector, which is why it burned. Definitely don't want anything that can burn anywhere near these bulbs, for exactly this reason.