Ann: NAB Chairman and Group CEO arrangements, page-4

No doubt we will see that sort of reaction from the tabloids. They will love the "shock / horror" of the early termination payment amount and obviously most people would love to see this amount be nothing.
But that's living in fairy land and even if the bod sacked him they would, without a doubt, have to make some sort of payment whether by agreement or through contract litigation.
Unfortunately even in small business it is a fact of life that you normally have to cough up to get rid of someone, unless the reasons are of a fraudulent / criminal nature or the like and this is more about reputational issues and being able to convey change.
Best to pay your money and move on...…………….
Incompetence can be expensive!!