Tigger too
The point is that you need pressure oxy to sustain activity below 80mps. For shortish periods you can easily work efficiently above 10000 cabin alt. I have personally experienced 15000 in air tests with no obvious impact (not at controls I hasten to add). Thus it is safe to allow crew to operate to 45000 without pressure breathing equipment since they would experience the relatively small shortfall for only seconds as they started descent. Concorde at 65000 was a different matter and had full pressure sets and mandatory baro cell/pressure breathing training for the pilots.