It's a smokescreen
First, if we are being real pragmatic, there is no contract without a dissmissal or release clause, whatever you want to call. It's usually money, and Kraft has no shortage of that
Second, there is no indication that this contract has been signed. It's all based on Rapoport's breaking news, so, at the very least, we don't have confirmation.
I can think of many reasons for this news to be made public, so it's all speculation. But, in practical terms, there is no reason to think that BB is unfireable, If Kraft indeed wants to