What happened was very unfortunate. I also wonder how it felt for him to fail miserably while fighting for his life. I suddenly realized how bad it would feel like trying to climb back up and not being able to hold on. Wearing no safety harness is already too risky. Not having a friend hiding on the other side to extend help in case of emergencies (just in my opinion) is plain stupidity. Having a partner standing by won't degrade the quality of the stunt. Audiences don't need to know that. Even Bear Grylls (in his wilderness survival show) get help from his crew.