You know what I'm interested in, if you can discuss it, is what was in your head just before and after the decision to stop and dig in. I believe many in your situation might make that panic/adrenaline filled decision to keep moving and trying, until it's too late.
How much doubt did you have about deciding to dig just before and after you did ?
Giving up my search for the route wasn't easy but after almost two hours and so many passes, the last few in the spruce, I had run out of tricks. The wind was picking up, if anything, and there was nothing to lead me to believe that conditions would change before sunset. I do second guess not returning to the summit and trying again to follow the Carriage Road down but that was against all my training and instincts. I still had an hour plus of daylight but waning energy.
Once the decision was made I didn't question it. I think you're a climber, Chip, so you may know the feeling when you run the rope out on hard stuff to a potential placement, only to find nothing, with another 20' to the next pro. A feeling combining dread with steely calm takes over with the certainty that there's no going back. That became my mindset. Once I found the bivy spot, I worked making the cave and was methodical preparing myself, almost as though, at some level, I had worked out the steps previously. Nevertheless, it was with great relief that I located each critical piece of gear in my pack.
As I mentioned in an earlier post, I lay there for the first couple of hours unsure of what to expect. Once things seemed steady state, I tried to construct a likely rescue timing scenario. Sue realizes the problem, gets authorities notified and so on. My calculation had possible help arriving between 11pm and 1am. I even thought of the crap I would take on this site upon my rescue! This schedule made the expected duration of my bivy, max 10 hours, tolerable. I was blowing my whistle at 15 minute intervals, four groups of three blasts, don't ask me why. I would shiver if I didn't exercise and refused to fall asleep.
After 2am, or so, I began to give up on rescue (ironically, my friends arrived at the summit then) and to concentrate on not just surviving but on getting out on my own. Maybe George Clooney had called Sue and told her he couldn't live without her. Rick who? I was obsessed with fear of decamping in the same conditions that had gotten me into this. The small hole I had poked in the sack to ease the condensation provided a peephole if I oriented it toward the gap between the ice shelf and the windwall. Sometime later, I peered out to see bright points of light above. Oh, yeah! At 7am, I made my move, described earlier.
Collectively, my replies in this thread serve as a trip report so I won't be posting one. Happy to answer any other questions, though.