We seem to have a similar problem with one of our four clinical instructors. She has been known to ask off-beat but on topic questions which makes everyone uncomfortable and very nervous that they will be failed for not knowing the answer. During our vital signs validation she asked the student to name several reasons why she wouldn't take a blood pressure in a certain extremity. The student about had a meltdown. So...our study group started coming up with a list of questions that we thought would be off the wall for the validation that we were doing and used those as we practice trying to simulate what she does to make us nervous. Another question that she asked once during our isolation validation was "Why would you not clean up the water drops around the sink after washing your hands?" A: It's housekeepings job. So, don't beat yourself up , just try during practice simulating what he or she does that makes you nervous. Hope this helps.