If your person to person interview is at their campus in Beaverton, Oregon?
Don't be scared, think of it this way, if things go bad, you were looking for work when you got that call. Nothing will have changed, no reason to be scared. Now, if they pick you up from the airport, there are dressed in black and wear sunglasses even indoors, and they escort you to a black SUV, then be VERY scared.
Seriously though, just relax, try and talk to the person as if you've known them forever. They can sense fear!