Andrew Thorburn was never going to survive the banking royal commission.The only surprise is that the announced date of the exit of the NAB CEO from the bank will be 28 February, a whole month after the delivery of Ken Hayne's final report.Ken Henry, NAB's chair, will hang around long enough to oversee the recruitment of a NEW CEO.For now, Philip Chronican, a senior hand at Westpac for many years, will act as interim CEO of NAB.The "global search" by NAB's board for a new CEO may, for once, deliver a global banker to lead a pillar of an insular Australian banking industry."I wasn't anticipating something of that nature," Ken Henry said of the damning assessment of NAB and its custodians in Hayne's report.Hayne, on Monday questioned the capacity of National Australia Bank's most senior officer bearers to take responsibility for improperly levying advice fees on customers and to fix the company's defective culture. The royal commissioner wrote of "a wide gap between the public face NAB seeks to show and what it does in practice".Henry, in canned comments, said "my decision is not made in reaction to any specific event, but more broadly looking at the bank's needs in coming months and years."