This person was none other than Ito Yuko, who had been crying in the room earlier.
At this moment, Yuko's face was calm. She was wearing soft-soled shoes, so her footsteps were light, almost imperceptible.
When she reached the area outside the tea room, Yuko stopped in front of the sliding door and listened intently. Sure enough, Kurosawa Tsuyoshi was moving around inside, the sound of tea being poured out coming from within.
Yuko then slid the door open and reached her hand inside. She knew Kurosawa Tsuyoshi would definitely see her, and he would certainly recognize it was her.
Thus, Yuko was confident that the very fact that Kurosawa Tsuyoshi saw it was her would cause him to be momentarily stunned, unguarded. And in that fleeting moment of shock, it would be enough for her to turn off a light switch.
Her calculation was indeed correct. Inside the room, Kurosawa Tsuyoshi was visibly startled as he saw Yuko standing outside the door, extending a hand inward.