Ascending with too little air is not a death sentence!
In the days of J-valves it happened much too often which is why we use SPG now.
In the early 70’s on a Jersey wreck I had bumped my J-valve down either on the anchor rode or the wreck itself and found my self without air. You put your head back to keep the airway open and start up knowing that at 90’ your lungs have 3x the air and as you ascend it will expand and bubble out.
Yes you are coming up with your bubbles which we now know is too fast but it’s better than the alternative