Magplug,
My Mistake. In the military aircraft that I flew that were similar to commercial aircraft the rear crew had oxygen masks which could provide 100% oxygen if required.
If the press reports concerning this incident are true it would still appear that the BA crew were lacking in providing passengers information as to what was happening. If the front end are busy I assume that it falls to the Cabin Service Manager (or equivalent) to inform the passengers?
Remote locking lockers and no bags under seats is the answer but that will never happen. Why should Flight Safety be allowed to over-ride commercial pressures?