The first agitator is where you begin at in the level. It is kinda of hard to tell what actually brings him out, but what I suggest is to kill all enemies before unlocking the door. It will take a while before all of them are killed, but you will know when all of them is killed when you actually see no one coming for you, no one in the tower, no one on top of containers, and you can't hear anyone. You will know when you kill everyone when Jill is hopped over the broken ladder and he appears right behind you. NOTE: YOU MUST NOT GET THE CHECKPOINT UNTIL YOU KILL EVERYONE!
Agitator #2 is near the end before you go into the communications tower. Get on the Grenade Launchers and start blasting at the bridge and kill everyone. Once everyone is killed the 2nd agitator will appear.
Agitator #3 is at the very end of the level. I don't know what gets this one to come out as he didn't come out for me at one time, but I am going to suggest to kill every boss that comes out for you and he should appear in the elevator with 2 Big Man Majinis.