In these lines from act 3.1, the conspirators are preparing to carry out their assassination plot. How does the dialogue between these characters reflect their emotions?

We are talking about Cassius speaking to Brutus and the main emotions that they reflect are a mix of anxiety and urgency about the scheme they are planning. When they say they fear they might be discovered when they say to each other: "I fear our purpose is discoverèd" or " be sudden, for we fear prevention"