Early on Friday 1 August 2008, Nicholas Rice made a mistake that may just have saved his life. He spilled a pan of water. The Californian was sitting in his tent at Camp IV on the shoulder of K2’s south-east ridge, preparing to leave for the summit. Getting ready to do anything at 7,900 metres above sea level takes a long time. Melting the snow for that pan of water must have taken an hour. It’s as if time accelerates, leaving you plodding along behind, taking an age to put on boots, an epoch to fasten crampons and zip up clothing. To a brain fogged from lack of oxygen, mistakes come easily.