I think When the student wants to go to the bathroom he's asking the teacher's permission should be accepted. Maybe I should have added for before teacher's.
In this form the sentence has no sense in either of the languages. Does this rule concern one definite student? Surely not. It must be "a student" and "תלמיד" without "ה".
you should add "washroom" as a correct translation of שירותים, for Canadian users
I think the app is wrong in saying "is asking" instead "asks"