Idk why some of you are saying Baek Han is in the wrong here. He even said Hong Lyon should punish the guards, he just didn't want her to kill them.
People are already comparing her to the crown prince, who was unpopular among people despite the fact he wasn't even king yet. Acting like a tyrant won't do her any good in the long run, that would just give ammunition to the people that want to overthrow her.
@Tersione
I don't think he had much of a choice, since it's been his family's duty for generations. Also, perhaps he thought the prince would be even worse if he wasn't there.
If you go back to earlier chapters you'll notice that he was always chastising the prince when he said or did sh*t, but the prince never listened. Chapter 21 is a good example of that.