The Bad
Much of what Kim could have done to improve this situation is obvious, but is out of her control at the time of the scenario. One of the key things she could still have done, however, was to call from the dentist's office earlier when she first discovered that she would be running late. This would have required some initiative on her part, but likely would have been possible to do.
The whole scenario could have been avoided by scheduling the interview at a time which would not conflict with other planned activities. In the event that a problem should arise unexpectedly, the potential employer should be contacted as early as possible. It is best to arrive for an interview approximately five minutes early and to be prepared to provide information or materials which might be requested.