go about one's business

To go about one’s business means to proceed with one’s usual activities or responsibilities, often with an air of detachment or disregard for external distractions or interference.

Historically, the phrase has been associated with maintaining composure or focus during times of upheaval or public spectacle.

It can also imply a deliberate avoidance of meddling in others’ affairs: Despite the commotion outside, she went about her business as if nothing had happened.