IS this not similar to an incident which occurred to a United 747 in the 80's? My mind is funny on it, but I recall a blowout or something of the main cargo door.
Yeah - that was to do with faulty locks on a door. That was my immediate thought when I heard this. But looking at the damage, I noticed the same cargo door is several feet away.
So I even checked close ups of the 744 to see if there was a door here and there wasn't. It's a strange case.
From what people on here and other sites are saying I do think something either exploded (not the O2 bottles) - perhaps cargo, or a loose container hit the skin from the inside (with great force), causing the hole, and loss of the section.