I thought the change in Dana's role was pretty lame. It felt forced. So far, she's been pretty wimpy, and suddenly she's all macho and active?
I agree about the security clearance issues, unless the country she's working for have some kickass ability to falsify documents and backgrounds... and I'm not buying that.
The security checks to work for a place like the CIA or etc. are extensive. They actually go talk to people from your background, in person. They'll interview your highschool friends. I have no idea how this character could have gotten around that kind of background check.
And I totally do not believe that in a high security facility like CTU, that parole officer would have been able to leave his conference room and wander, as he did. Even in my old company, which was merely medical devices with government contracts, that could not happen. It literally wasn't possible for a guest to leave and wander without causing immediate notice.