Michael has ice water in his veins in that scene. He calmly tells the nurse to stay put, sarcasticaly tells Sonny he "won't panic" hatches a great plan fr Enzo the Baker, and after the car drives by, calms the nervious Enzo by ighting his cigarette, telling him he "did good," and shooed him away before the police oculd get their hands on him. In the process healso managed to tell Vito he was "with him now," stood up to McCluskey telling him he would not move until men came to protect his father, and took a hard shot to the jaw.

Nothing nervous or afraid about any of that.