I don't know why you guys are spoilerizing that. The lie detector was on the table next to the terrorist when he made the comment about the yoga class. That was in this episode and there is no need to spoiler tag it. That said, assuming that Carrie is given a lie detector test, she would probably be able to beat it. I'm sure most (all?) spies are taught how to beat them. Further, her "crazy" would throw off the readings anyway.