The pilot is (was?) the commander of an aircraft. To sit and play David Bailey whilst No2 was outside chatting with the purser (is that the new name for loadmaster/doorman/head steward?) and a mate of his is, in itself, not exactly military. Plonking his camera down next to a primary control just smacks of complete ignorance.
Sorry, but MAA/MilAAIB can flower this up with all sorts of useful chain-of-events and Swiss-cheese stuff but the bottom line is the whole incident makes the RAF AT fleet look like a bunch of amateur........ photographers.
As Airbus say, it's the first time in a squillion hours that this has ever happened.