Remember that if you ask someone about their viva you are going to get a picture of what happened, and not the event itself. Not all of the details will be clear and perhaps some of the things you really want to know will not be present in their story.
It’s like looking at someone else’s holiday photos. Holiday snapshots show things someone else noticed or were interested in. At first, talking about it might only give surface impressions, the short version of what happened.
Every viva story is a snapshot of an experience. A viva story doesn’t reveal everything and without context could even be confusing. Ask about what you need to know. And ask the right people! It makes more sense to ask a few people from your own department about their viva than trawl the internet for lots of stories.
Figure out what you need to know to have more certainty for your viva and your preparations.