Kyung-Soo was happy after receiving Nivritti's message and happier that now he was alone, and Jung-Hwa wouldn't barge in any time soon. After Nivritti did the ceremony to send away the imaginary ghost, Jung-Hwa had been sleeping peacefully in his room, and Kyung-Soo got his room back. Well, all got their rooms back.
Otherwise, Jung-Hwa would barge in whenever he wanted, and if he had seen Kyung-Soo jumping and squealing, he would have made fun of him. Not only that, but he also would have babbled about that to everyone.
How Jung-Hwa kept the fact hidden that Kyung-Soo liked Nivritti was unthinkable. He had no idea that Thae and Jeong-Eun knew about his crush. They were witness to what Jung-Hwa did in that bathroom.
