For my simple A.I enemies I eventually realised it was best to set the priority for each of the states. The ultimate and un-overridable state was the death sequence, then the recoil or falling of a ledge, then attacking, then the sort of neutral stuff could mix and match as it wished. I hope you understand this...basically I think switches/states is fine...just get them in order and check if they have permission to execute their particlar sections of behaviour code - A hierarchy of sorts.