The viva is a discussion. Questions are asked to prompt and probe; responses are given to move the conversation along. Your examiners ask questions and make comments to explore your research and your capability.
If your examiners disagree with you in the viva: ask them questions if needed, then listen and figure out what – if anything – you have to say in response.
And if your examiners agree with you in the viva, then the process is the same: ask them questions if needed, then listen and figure out what – if anything – you have to say in response.
It’s understandable why any candidate might worry about examiners disagreeing with them. It’s helpful to remember that disagreement does not mean failure. It’s helpful to remember that you can engage with critical questions and comments; that’s what you’re supposed to do as part of the viva.
It’s also helpful to remember that the vast majority of vivas are successful.
