To the outside world, John Ryan’s future seemed mapped out ahead of him. He had completed his finance degree in UCC, before joining the corporate world with the stockbroker Goodbody as an equity analyst. But Ryan had other ideas. He liked the world of finance, but, even as a student, his mind was gravitating elsewhere. He wanted to challenge himself physically, psychologically, even spiritually. He wanted to know how far he could push his mind and his body. So, in 2007, he joined the Irish Defence Forces as a cadet, eventually graduating top of his class.  Over the following decade,…