As we know about Kazakiri Hyouka, nobody has seen her and knows about her appearance.In episode 21 at 16:15, Yomikawa tries to confirm the existence of the 2nd outsider with Tsukuyomi Komoe. Later, in episode 22 14:25 Tsukuyomi Komoe states that Hyouka didn't appear on any surveillance cameras in the school, but later, in Game Center, she appears in a photograph taken in the photo booth, with Index. It might be possible because she manifested in the real world when she touched Index. But she should have before after that, while getting leaving the school.
Tsukuyomi Komoe does say that nobody knows how she entered the school, but doesn't talk about how she got out without appearing on camera. But Yomikawa's question does imply that she didn't appear at all.
Yomikawa might have viewed all the footage and looked for info about the outsiders but didn't find anything on Kazakiri Hyouka.
So why wasn't she seen in the surveillance camera footage after she manifested in the real world?