This is a major design flaw -- you must be able to shut down an engine either from the cockpit or, in extremis, from some kind of inspection hatch in the passenger cabin
I disagree... to the extent that already there is clearly
'a major design flaw'
The principle requirement is that engines do not suffer "uncontained failures". We know they do, but that is the aim. When the aim fails (as here), it does so in an unpredicatable pattern, and impossible to design against in a specific manner.
Assuming the A380 is like other Airbii, you can shut the engine down via the Master Switch or Engine Fire pb. I agree, if these 2 are routed via the same loom, that is not sensible... and some sort of separate paths should be required. However, if the routes are separate, and were taken out by bad luck, so be it.
I'd rather have engnes running when I didn't want them to, than numerous stopping methods / boxes that mean I have engines not running when I do want them.
NoD