The Final Break
Vivas often conclude with a short break. Your examiners will need to have a final discussion between themselves to confirm the outcome, maybe to confer on corrections or even check what regulations says about how they pass the decision to you.
These intermissions typically range between five and twenty minutes. This is long enough for a PhD candidate to get really, really nervous: after all, there’s nothing else you can do at this point! No more writing, no more talking, now you’re just waiting for the result!
With nothing else to do in those moments, I’d suggest deciding in advance what you will do to pass the time. You don’t know in advance how long you might have, but you can decide, I’ll go refill my water bottle or I’ll just step outside and feel the breeze.
At the end of your viva, having something to do when there’s nothing else you can do is a really good idea. It’s a lot better than simply waiting.