I would strongly advise against depressurising and staying at altitude.
At 34,000 ambient pressure is only 188mmHg, so 100% oxygen would supply a pulmonary partial pressure of 101 mmHg, after allowance is made for 87 mmHg of water vapor and CO² in the lungs. As passenger & Cabin crew oxygen systems are not designed for pressure breathing both would suffer increasingly severe hypoxia above this altitude, those that failed to wear their oxygen mask would quickly lose consiousness.
Aircraft with chemical Oxygen generators (not the 146, I know) have only about 12 minutes of Oxygen available (and you still have to descend remember!) and the generators themselves put out a lot of heat.
More importantly perhaps, keep the aircraft cabin at such low pressures and Nitrogen will come out of solution in the blood and fatty tissues and form bubbles, know as Dysbarism or Decompression Sickness, in the passengers and crew (including the pilots!). Get the bends and you may not be able to recover the aircraft later.