...that's what you have at 38,000ft.... 12 seconds of useful consciousness.... not long!
Imagine a scenario where, say, the windscreen goes. All of the paperwork in the flight deck gets thrown into the air, several kilos of dust from every surface in the flight deck is sucked into the air also, visibility reduces. You've got 400 kts of headwind in your face. The loud roar this produces makes communication impossible. Your ears are agony. Any trapped air inside your body is agony. Maybe you've been hit by parts of windscreen blown into the flight deck and you're injured.
With this as the backdrop you have to fumble for your oxygen mask and get it on. A a previous post said..
If the masks are donned in an unpressurised aircraft at FL380 they will not provide sufficient O2 for the crew as there is insufficient partial pressure to breathe. The mask must be switched to the emergency setting (unless A320 has a different system) to provide ram air O2 to enable breathing. If this was not known or done by the crew then the mask would be of little use.
So you've donned your mask, maybe it's not set to 'emergency' setting. You cary out the initial items of the emergency descent drill which include 'pull altitude knob and turn' (set to FL70?) Remember at this stage you are not checking the value you have set it to. At a later stage in the drill you are to return to the alt knob and set FL100 or MSA (whichever higher) but before you can get to this stage your 12 seconds are up. So the aircraft continues in a controlled, thrust idle, descent, with 2 unconscious crew in the flight deck and FL70 set in the window.
At FL70 (6800 feet) the aircraft levels off and you are now below the level of the terrain. We know what happens next.