You are all incorrect. Yukari is just upset that Yuyuko discovered she was cheating on her with Ran, and is debating with herself whether erasing their memories would be despicable even for her. Yuyuko is too shocked to react, and Ran, being the dutiful subordinate, is immediately ready to serve her master's friend despite her state of undress.
Extraintrovert said: You are all incorrect. Yukari is just upset that Yuyuko discovered she was cheating on her with Ran, and is debating with herself whether erasing their memories would be despicable even for her. Yuyuko is too shocked to react, and Ran, being the dutiful subordinate, is immediately ready to serve her master's friend despite her state of undress.