[publius911]

That bulkhead is not thin material, is very strong...and was blown backwards and apart from something that occured in the cabin.

Like what?

Just look at the most recent pics of that bulkhead. Thin is a relative term. it's peeled back like a tin can.
At altitude it must withstand something like 10 tons or more of pressure. Seconds from touchdown, the internal and external pressures had to be equal.

So, like what? An out-of-control food/drink service cart just prior to landing? What?

Ten tons or... ?

[BatGuano]

I’ve seen the Aft pressure bulkhead on the B777 while on a floor tour of the Boeing plant. It is made by Mitsubishi and it may have been “peeled back like a tin can” but I assure you that it was intact. It must have been torn from the fuselage structure that failed along with the Vertical Stabilizer.