The AP story in local paper said the mother was a marathoner and triathlete. The family agreed she had the best chance of getting help. She has serious frost/hypothermia damage to her hand(s).
Local sheriff said:
“Google Maps shows there’s a way — but it’s impassable,” he said, adding. “This is a problem we’ve had numerous times.”
https://www.abqjournal.com/915300/searchers-rescue-family-stranded-in-snow-near-grand-canyon.html
I probably would have left the safety of the car also... it’s a Type A flaw that many of us have. Totally understandable that she went for help.
As far as being .2 miles short of a marathon, looks like she has done many.
If it were me, I would have asked the ambulance to drive along side me for another 1100 feet as I hobbled along, maybe with an IV plugged into my arm to reach 26.2