25 minutes sounds a bit hopeful to me as well.
When I did the course at Boscombe Down the chamber was depressurised to 25,000 ft, and the three of us on the course took it in turns to do jigsaws, and after 2.5 minutes I was trying to fit two pieces together with one of them vertical, so I don't think I would have been much use at the controls. (I wouldn't be that much use anyway, as I'm not a pilot, but you get the idea).
It was an interesting experience, and bloody good fun as well.