I never quite understood why FSM enters the AI realm, nowadays too many topics fit into the AI category..

Anyway the idea of FSM is simply a case, which in each node you can have several options, for example an enemy in FPS:
Code:
Our object can be: [hurt, healthy, hiding, hunting]
Case object_state:
  Hurt: do hiding.
  Healthy: do hunting.
  Hiding: do hiding until Healthy.
  Hunting: do hunting until hurt.
Of course it should be a lot more complicated with several cases for each state in order to accomplish a believable “smart/real” enemy.