A Member first directs any criticism of the professional activity and related work of a colleague to that colleague in private. Only after informing the colleague of the intent to do so, the complainant may direct in confidence the criticism to appropriate officials through the proper channels of communication.
In this situation, quietly changing the subject and raising the issue later and in private with your colleague is your best option. Article 1 and 5 of the MTS Code of Professional Practice focus on our professional responsibility to our students and the importance of maintaining confidentiality. This responsibility extends to all areas of the school, including the staff room.