I might be wrong but I highly doubt that was from a +p round, not a factory loaded one anyway. That is either a way over loaded hand load, or a squib, which I'm pretty sure that's what it is, squib load. I've never seen a +p round do that, +p is only about 10% hotter then standard, it will wear the gun for faster but there are several videos of people shooting +p in the DB9 and it didn't blow up at all.
I stand corrected! I emailed DB and we CAN shoot +p in the Gen4. I apologize for my error.