Try not to overthink the viva.
It’s an exam, but just an exam. It’s an important conversation, but still just people discussing things. They’re asking questions, simply looking for honest responses.
Each question is a chance to add something to the viva, but is also just a question.
Preparation is about getting ready, not being perfect. Photographic recall and encyclopaedic knowledge are not required.
Overthinking won’t help you prepare for or get through the viva.