the only problem is that if there is no running jet engine, there is no more oxygen (produced from bleed air) and the oxygen masks last for 10-20 minutes...
The APU would still be able, to an extent, to provide pressurisation even if both engines are disabled.
I would guess that the cockpit has a longer supply and perhaps they could descend faster to a safely survivable altitude. You’ll be able to pick up speed doing so and so a lot of that energy for gliding is still available, though some extra would be wasted due to the higher speed and longer time spent in higher pressure atmosphere.