Canberra mountaineer Andrew Lock felt no fear when he found himself atop Mount Everest with no oxygen and worsening symptoms of altitude sickness.
A trip to the summit to film a documentary in May 2004 turned into a precarious mission to rescue three climbers who had run out of oxygen and were clinging to life.
Mr Lock, an experienced adventurer who didn’t usually climb with oxygen, had carried three bottles of gas needed to survive the 18-hour return trip to the peak that day.
As he began his descent in the afternoon he came across three climbers from Britain, Mexico and Canada who had run out of oxygen and were suffering from various stages of cerebral oedema.
