To be fair, you both currently under Yggdrilsil by orders of its superior. No official chain of command has been established between the two of you. While its usually  the job to keep the other three Divisions focused by the observation division, being in it doesn't automatically make one a superior over the others. Same reason a Marine can't just go ordering around privates of the army: different jurisdictions, who only need to follow the commands of their supreme leaders.

 That being said, I approve of this development. Tori's talents would be better with the Librarians since only one person has her counter.

Also it's more like the member of the CIA against Homeland Security. Operating the library just happens to be one of their other jobs.