To KiloB:
The 'bent outwards' piece of hull near the top of the picture has a suspiciously even and rounded edge on one side. Almost as if it got in the way of a cylinder going somewhere in a hurry!
Indeed, like if that piece of structure has been punched out. Like many posters have addressed, an O2 bottle does not just rocket out of an aircraft. There is probably more to the sequence of events which a thorough investigation will reveal.
Also, it is not possible to tell from the pictures how large the initial hole was. I do believe, however, a force large enough to punch out the skin also took out the lapjoint and thus, was part of the initial damage done to the structure. Decompression and aerodynamic forces probably made the hole much larger, ripping away jagged pieces of structure which were fluttering in the disturbed airflow due to the shattered fairing which most likely separated from the aircraft at the time of the structural failure.
Regards,
Green-dot