The fate weaver was on the wall operating the traps manually. What she was using to control the traps was a large array disk with many lights and switches on it.
The lights indicated which traps were online and ready to be activated. Currently almost every light was on.
Only two lights were dark. They belonged to the two baristas. Those two have just shot their payload and need time to reload.
The array disk was on the table in front of her while she was overlooking the scene below. She also had an abacus in her hand. She would look down and make calculations on the abacus.
The calculation wasn't purely mathematical. There was also a spiritual component because she was using her rank 1 Predict. These two, combined with the information she gained by observing the situation with her eyes, helped make the best judgment.