Hypoxia, and the lack of practical training received by our contractor pilots, is one of our biggest Risks to Life (RtL). Consequently, we recently went to RAF Henlow to receive some excellent training. I haven't done this level of training since leaving the RAF over 12 years ago, and I would thoroughly recommend it to those with a need and a budget. Furthermore, they have a part-task trainer, so you don't even have to go into a hypobaric chamber anymore.
The advice to stay at height - especially if the cabin alt is above 25,000 ft - is unwise. The RAF use 25,000ft as a cut off for pressure sickness, with 10,000 ft being the safe altitude before the risk of hypoxia increases significantly.
Pressure breathing is vastly different to having an over-pressure. Draegar Hoods are not effective above a cabin alt of 25,000 ft.
Aviate, navigate and communicate while you can. That should call for an immediate, controlled descent to below 10,000 ft, depending on the SALT.
The SAMs may get a 'cheap kill', but lack of oxygen will certainly send you to 'the great bar in the sky'. And debating about what to do in such a situation won't help your cause.
Fly safely!