The Music Director (MD) of a theater show is at the center of the noise - lots of noise.
All at the same time, a MD is:
Watching the stage;
Cue'ing singers to make their entrance;
Cutting off choruses;
Listening for balance;
Cue'ing musicians to enter;
Cutting musicians off;
Maintaining balance across the orchestra/band;
Playing their own part;
Listening for cues to start the next song,
Listening for cues to finish the vamp;
Making notes for future shows;
Wondering if the sub that's playing the keyboard 2 book ever took a lesson;
Thinking who will play the keyboard 2 book after they fire the sub; and
Not saying a word.
The MD stays at the center of it all.
She never gets too far ahead.
She stays present, calm, and still.
Waiting for the next cue.