First of all, thanks for the translation, it's honestly enjoyable to read. Now, there is only one thing I noticed at a glance with my half asleep brain while reading this for relaxation... and some others have noticed before. It's 300% constructive criticism, so don't take it badly!
"You guys" could have easily been replaced with "You two" for a more formal, but slightly demeaning way to refer to them by someone of a higher standing, or "You both". The use of "you" is already derogatory in such a formal situation, as it tells the parties that whoever is refered to as "you" is a nobody without a name, a title, or a position that matters to the involved parties.
The main issue is, "guys" belongs to a very informal setting, so it clashes a lot with the whole thing and just looks wrong, even to my sleep deprived mind. I understand where you're coming from since the og text likely tried to put down the two kids in the conversation, it's just that "guys" is a bad choice, since, well, it's also a word that besides being informal, is also one that determines closeness and a certain degree of intimacy.
And really, besides that above, the word was actually noticeable because everything else was well done, so it stuck out like a sore thumb. If you had said it was on purpose because you disliked that reformatory director, I would've completely believed you ahaha.
Anyway, my 2c, hopefully it wasn't a waste of time to read me. Keep up the great work.