Script Supervisor Dilemma: Spontaneity vs. Schedule on Fast-Paced Sets

Hey everyone, Megan Foster here, working as a Script Supervisor. I'm hitting a wall with something that comes up fairly often, and I'd love to hear how other experienced folks handle it. We're always striving for that perfect shot, often with pre-vis and detailed rehearsals to nail things down. But then, an actor will sometimes deliver something completely unexpected and brilliant in a take (a glance, a gesture, a line reading that wasn't planned) that truly elevates the scene.

On a micro-budget short I just wrapped, this happened a few times. We'd have a clearly defined shot list, but an actor would bring real magic that meant straying from the original blocking or even the camera movement we'd prepped. I tried to note it and discuss it with the director, but sometimes it felt like we were either sacrificing a great moment for the schedule or blowing the schedule for a great moment.

So, my question is: On a fast-paced set, how do you decide when to completely abandon a meticulously planned shot for a moment of spontaneous actor brilliance, and critically, how do you then manage the inevitable schedule impact without derailing the day completely?