@jwkinraleigh
no, check chapter 12. She prohibit their entry in the future, but not with magic seal or something. It's not so convenient. She just stated that she wouldn't serve them anymore and would just force them out if they return.
It's definitely one of them, just look at the face.
Edit: scratch that, i checked the novel, and it's definitely barrier that prohibits entry. That said, it's still indeed those mercenaries, but they just pointed a gun from outside of the door. I don't know how they were able to enter here.