Is staying alone with a girl haram in all situations?

For example, if someone in school got in trouble and he got sent to the (female) counselor's room, and there is no person but the counselor and the boy in the room, would he be sinning in this case because he was alone with a woman? What if the door was open and other people weren't far away, but still out of sight? Because of the hadeeth: >قال نبي الاسلام عليه الصلاة والسلام : " ما خلا رجل بامرأة إلا كان الشيطان ثالثهما " Jazakum Allah khayran,