If, as Sandilands alleges, Joyce is shown to be a liar then the damage to Qantas is complete for one very simple reason:
Every employee of Qantas now has permission to lie to anyone - customer, regulator or fellow employee - Joyce allegedly gives it to them.
You cannot operate to your AOC if you are not a "Fit and proper person' and there are multiple precedents of CASA requiring the removal of Directors and managers from any association with the running of an airline, on penalty of cancellation of the AOC.