I just wanted to know hypothetically. Like for a babysitter or a teacher on a field trip. For instance if you went a play for a class Field trip and the child got upset at a scary part so you take the child out find a building next door to the theater where there is an office and toys and a bathroom. You both have to go so you let him go first but since there is no one else there you tell him to face the wall and he does and you do your business quickly without him seeing anything then you both leave the bathroom.
Without more, the facts you describe do not describe an offence known to Canadian law.
It is hard to prove a negative (you would have to review the entire Criminal Code), but you can review the various sexual offences (s. 150 onward), and offenses relating to public nudity, indecent acts or exposure, or voyeurism. All of these would require more than what you've described.