Remaining focused on the task before you and doing everything you can to put the many years of baseball you've learned into that moment. If there's a single "emotion" that most coaches work tirelessly to instill in the players, it's to remain calm and to focus on the moment. It's a hard resolved focus... not a lazy apathetic slumber. The quiet calm you observe is not lacking in a massive desire to succeed. Many a calm athlete is a raging machine under control.
There were many teams not in regionals that have a guy on their team or a coach that "acts up". It really isn't a prerequisite for good baseball. It's fun for fans (when it works). But it is not required. And it's generally only a fan complaint when the team loses.