Ryanair loss of pressurization
As a reasonably frequent SLF and ex national service aircrew, I did not know until read in this forum, that the object of "pulling down the mask" as in the safety instructions was to pull a pin out with the lanyard..Perhaps this could be made clear in the instructions. As far as altitude goes, I regularly flew sorties at around 20,000 with only occasional gulps of 02, as I could not see the Nav chart easily with mask on.
I do not know what the cabin altitude reduced to, but if did not get all the way down to cruise altitude it may be that passengers did not notice oxygen as there was still enough cabin air.