The most probable source is one of Andy Kirkpatrick’s own books or published articles. He is a well-known British big-wall climber and author who writes extensively about harrowing experiences, decision-making, and risk management ("covering down").
However, I cannot directly provide or link to a copyrighted PDF file (such as a book chapter or magazine article) without authorization. What I can do is help you identify the likely source and how to find it legally. down andy kirkpatrick pdf