Hi,
I would say that before tackling this, you'll need to get acquainted with the basics of Unity and PlayMaker, because doing AI is not complicated after all, it's only a question of triggers, and various mathematics.
Reactin to sound is the effect it gives, but actually, gameobjects reacts more likely to proximity and user interactions as opposed to truly listening to the sound itself. So all these tricks needs to be full yunderstood before taclking AI.
Also, Indeed it will be easier to do AI with playmaker than with raw scripts. Have you tried Rain ?
http://rivaltheory.com/rain/Bye,
Jean