Cabin V/S message
Quote from HN39:
"...if it [the negative relief valve] did not open, then please come up with a mode of the CPC that would command the cabin to climb or descend at a rate greater than 1800 fpm. I believe that to be so improbable that it does not merit discussion on this thread."
takata and I have argued about this before, but I think there is one very remote possibility.
If at 0214z the aeroplane was still at medium-to-high altitude, a failure of both packs (or a double engine-failure) would cause a positive cabin VS (loss of cabin pressure) until the outflow valves had a chance to close. This might exceed +1800ft/min, falling (hopefully) to +500ft/min or less with the outflow valves closed (depending on the state of the door seals). Outflow valves closure might be automatic by a serviceable CPC, or by crew action if not (see the drill on takata's post).
However, I would have expected double pack failure and double engine-failure both to be ahead of cabin VS in the ACARS message hierarchy - they would be in ECAM hierarchy.