Myles Clarke was trying to make sense of the chaos. The trouble was, the chaos was everywhere; like a virus, it was mutating swirling, evolving.   Lehman Brothers has collapsed, unleashing a wave of market turmoil. Panic has infected the financial system.  Less than a year before, in August 2007, his employer RBS was part of a consortium that took over the Dutch bank ABN Amro. It was the largest deal in financial services history and, for a short period the following year, RBS was the biggest bank in the world by assets. When he joined the bank, his boss took…