Talk:Mei Misaki/@comment-78.129.92.156-20180803154301/@comment-6052796-20180809060051

Because Class 3-3 has been making up countermeasures as they go along. Since they started they only knew the rules of the calamity through trial and error. They were aware there is an extra but until Mei came into the picture no one had a means of detecting the Extra. And even then no one at the time save for the man that made the recording and even that got erased from his head; knew about what to do if they saw the extra. Kouichi suggested they pretend the extra doesn't exist, which was left ambiguous, leaning towards failure due to the fact that they were into the school year to make that change even if they did know who it was.