User blog comment:AquilaeAltair/OnS Theories. Fourteenth Theory - Shiho Kimizuki. A traitor or a person who understands the situation the whole squad is in./@comment-36009152-20190511115634/@comment-36009152-20190904183910

The thinking might be Yu is fine no matter what, more so with one strong bodyguard in Mika with him XD so Kimizuki feels all the more reason he needs to focus on himself and who he can protect, namely his sister.

Then again Kimizuki shows he cares for everyone, need them to rejoin as a squad once more!