The meaning of “she sliced through negativity”

The meaning of “she sliced through negativity”

The passage below is from The Island of Sea Women by Lisa See.

My mother knelt next to Do-saeng. Soon the rest of us were on our knees in a circle of anguish. The shaman held ritual knives in her hands from which white ribbons streamed. As she sliced through negativity, the ribbons swirled around us like swallows through the air. Her hanbok ballooned in clouds of riotous color. We chanted. We wept. Our emotions flowed from us accompanied by the cacophony of cymbals, bells, and drums played by Shaman Kim’s assistants.

The scene is a shaman performing a rite for a lost soul. Here I cannot clearly visualize the scene of the underlined part, ‘she sliced through negativity’. Slice means to cut. I looked up dictionary to see if there’s any special meaning I don’t know about in negativity, but couldn’t find none to fit in this context. Could you help me out?

Thanks in advance.