Examiners aren’t looking to find fault. They might have tough questions, they might think they see problems. Because of their experience they could have critical comments but these are never aimed at tearing work apart – or trying to tear a candidate apart.
In the viva, if something doesn’t seem right to them, instead of finding fault they could be looking for you to take responsibility. They don’t want to know who is to blame, but rather why something happened that way.
Sometimes mistakes are made. Sometimes, with good intentions, a plan of work doesn’t work out.
Taking responsibility doesn’t mean simply saying “It was me!” but rather exploring and explaining what happened, what you did and why things are the way they are.
You’re not at fault, you’re not to blame, but you have to take responsibility and then see what comes next.