Substance, Not Surface
At the viva you are invited into a discussion.
Of course you’ll respond to little questions for clarification and confirmation, but the overall drive of the viva is towards conversation.
It’s not a quiz or game show where the fastest answer wins. Your examiners want your considered thoughts and ideas. They want substance, not surface.
Do the work. Prepare well. Listen to the question. Take your time and think. Be as clear as you can be.
Which is all to say: do your best. That’s all your examiners are looking for and all anyone could expect.
Deep questions require more than surface-level responses.