I have some anxiety about public speaking or presenting to a group. Not debilitating but more than normal, or so I feel. But I find that once I get going it fades. Starting off is the peak of stress. So if the examiners are trained how to encourage a person to start talking, perhaps with some introductory conversation, and when questioning not being confrontational, that might help. The goal is to find out what they know, not how polished their presentation or debating skills are.