Would you cut off one of your limbs to spare your life?

I read a Reader’s Digest some time ago about this man hiking alone in the high desert. As he tried to descend a gully the rocks beneath him shifted, he tried to grab hold to some of the boulders near him but cause them to shift as well. So in the end he plummeted 10–12ft down the gully and one of the boulders landed on his arm pinning it. No matter how hard he tried he could not get it free. After spending 9 or so hours stuck there and not a sole sighted or any search planes looking for him he felt he had to make a move. His water almost gone, and fearful he would die of dehydration in the hot sun or from the elements he felt the only choice he had was to use his knife and cut off his arm to free himself from the boulder. To save your live would you cut off an arm or a leg? Do you think you could stand the pain? What if you started and the pain made you pass out, do you think you would bleed out before you gained consciousness? And if you are successful how would you be sure you won’t bleed to death before you got back to civilization? I know some will think they will whip out their cell. Really? In the high desert? You think you would actually get a signal?