you dont tell your chief that there is an angel right under your nose? What happens when the chief invariably finds out that she is an angel anyways? Then you are actually commiting treason, instead of just being in a sticky situation. Is this the first situation ever in which magical collars are used to force someone to obey them? Why not just tell the chief who the angel is, and let her deal with the rest? There is a limit to the suspension of disbelief, and I feel like this manga is crossing it.