I believe the Pathfinding AI is one of the things designed to drive you crazy. And, I think Westwood actually copied theirs from Bullfrog. Ever done Command and Conquer? "I'm a harvester and I am looking for a way back into mybase. Oh, hey, there is a LOT of commotion at the enemy base, let's find out what they do and bring some back!"
Yeah.. loving that. However, luckily the same errors apply to the enemy agents. I had a ton of agents run at mo more than once in a straight line. Perfect for "laser tag".
Certain missions were literally one-shots =)