I recommend handing over the interview questions to job candidates when they come in for an interview. Give them a few minutes to look over the questions and collect their thoughts, then let them answer the questions in whichever order they choose.
By doing so, you reduce the tension on all sides. In essence, you let them interview themselves while you take notes and ask follow-up questions.
There is an unnecessary adversarial or "gotcha" aspect to many parts of life.
Remove it and you can achieve better results.