Post event briefing?
I'm very happy so say I have never heard the briefing after a depressurisation event, but it sounds as though there is scope to improve the reassurance element of this briefing.
Could it usefully include an observation that the descent was a well rehearsed safety procedure, and confirm that the oxygen supply to the masks is a trickle feed rather than a pressurised delivery system?
This might help passengers to understand the episode they have just been through, and save them the embarrassment of making uninformed comments afterwards..