I checked my balance and peered apprehensively at the sheer drop below. Once I felt comfortable, I radioed down to Stu. 'I'm just gonna unclip quickly,' I said. My walkie-talkie crackled straight away. Stu sounded pretty stressed. 'Dude, keep the rope on!' I edged forward, my hands and feet scoping out the summit for any loose rock. The ridge pinnacle...