They might be the people operating the lights, making the costumes, painting the stage, and that sort of thing.
他们可能是操作灯光、制作服装、粉刷舞台等等的人。
英语百科
Surgical lighting
A surgical light – also referred to as an operating light or surgical lighthead–is a medical device intended to assist medical personnel during a surgical procedure by illuminating a local area or cavity of the patient. A combination of several surgical lights is often referred to as a “surgical light system”.