>>6489566Mate I'm not sure what you're getting at, if you're cruising at the upper average altitude of 40'000ft its going to take you a maximum of 20 seconds to pass out in an at rest, non panicked, not explosive decompression environment. In reality probably less than half that.
Realistically it will take about 5 minutes for the aircraft to descend to a the upper levels of unaided breathable atmosphere.
Where is the girlfriend in all of this. Is she theoretically remaining in control? Does she have breathing apparatus? Why is decompressing the aircraft? Is it a by opening one of the doors? If so how is she not going out with the air?
Why don't you just go mess about with breath play apparatus like a normal person and stop dicking about in controlled airspace. You're going to get an SRG1601 filed against you.