There is always one person who is designated as "bad cop" and will antagonize you and make you try to second guess yourself....Some sample questions from my interview:
To me (I was a chem major): What is the definition of a calorie?
Other people: What % of the atmosphere is oxygen? Guy doesn't know so they tell him 21%. Then they ask, ok so what % of the atmosphere is oxygen on top of Mt. Everest? Trick question...same % just less of it.
Some question about $1 billion in healthcare money being allocated equally to all 50 states, so how much does each state get?
If a Jehovah's witness patient is bleeding out on the table do you give them blood products?
Anyway, you get the idea.