Even if one accepts that the oxygen bottle returned back down through the hole in the floor and then punched out through the fuselage, there would have been metal deformation typical of stretching at the point of failure.
At the point of failure however the fracture is along the rivet lines.
In a stretch caused by impact from inside you would expect the rivet holes to have elongated not laterally, but longitudinally.
You have expected each individual rivet to have torn away from the frame or stinger beneath, but instead the metal has cracked along the line of rivets.
The accident investigation report appears to have been a political response to exonerate Qantas from engineering faults rather than based in physics or fact.
Another point is why if the oxygen bottle as investigators suggest punched a hole out from the inside did the stringers or frames not deform. It is clear in the picture that the skin tore away from frames beneath, but the frames underneath were not themselves deformed.
Packrat, it's called Ockaham's Razor ... Look it up sonny.
