I like the theory that he is UNIT, but ex-UNIT, as going out with Clara would obviously cross some boundaries if he had been assigned to keep tabs on her / the Doctor / the school.
He comes across as a bit jaded concerning traveling in the Tardis or into space, hence the ex-UNIT idea. Not sure if he knew who the Doctor was, but again, he was not too freaked out by the Blitzer, either. If he was active-duty UNIT he would know who the Doctor was (at this school, anyways) and would not have removed the Doctor's devices.
He comes across as a bit jaded concerning traveling in the Tardis or into space, hence the ex-UNIT idea. Not sure if he knew who the Doctor was, but again, he was not too freaked out by the Blitzer, either. If he was active-duty UNIT he would know who the Doctor was (at this school, anyways) and would not have removed the Doctor's devices.



