LAST TIME ON CORIOLANUS: The people of Rome, riled by the tribunes, decide to revoke their support of Coriolanus as consul. The tribunes confront him and, in typical Coriolanus style, he totally loses his rag and goes off on a long rant about how lousy and useless the people are and how their tribunes are a blight upon the noble senate of Rome. The tribunes are furious, and declare him a traitor who should be put to death. Menenius urges Coriolanus to go home and attempts to reason with the tribunes, promising them that he will bring Coriolanus to meet them and the people and resolve their differences.
Coriolanus doesn't listen to anyone. Except his mother. He listens to his mother. This is one of the things you need to take away from this scene.
"Don't lose your temper, Coriolanus." Possibly the five most futile words in the English language? A strong candidate, anyways.
Everyone always talks about Coriolanus's reaction to his banishment, namely his "I banish you!" proclamation. It's a classic "You can't fire me - I quit!" moment, and is a perfect reflection of how his mind works. He's completely in control of his banishment, a fact that comes back to bite Rome in the proverbial butt soon enough...