Near the death zone on K2, the world's second-highest mountain, Lisa Thompson searched for the strength to continue climbing. Her choices were clear: give in to her doubts and descend or push past her own limits and continue up the mountain's steep face.  Defiance had provoked Thompson to enter the male-dominated world of high-altitude mountaineering, but defiance could only take her so far. After a harrowing battle with cancer, Lisa realized she...