I don't know. I feel like this is the second real conversation that Dowun and her have had since she returned. She answered him without hesitation unlike many of the other times where she had to explain herself. She also acknowledged his point and seemed more aware of her position, politics, and more generally more balanced than she's been since she's become Queen and Baek Han re-entered her life. She's also sitting there doing work that, by all appearances, hasn't been pre-stamped by Dowun. What if the "she's reverted back to her old self" is actually him commenting on how she's past her emotional turmoil from slaughtering her entire family. The "time to make my move," while ominous, might not be a greater threat to Lyon at all. We know he's been waiting for enough time to pass to remove Baek Han. He could have also decided to use Baek Han's warmth as a tool to help restore the Queen to her senses. If that's the case, he is now a greater hindrance than he is an asset.
EDIT: On second readthrough, there is an ellipsis for a pause. I still say she spoke more directly and gave a genuine purpose behind her actions. Similar scenes in the past have shown her body language to tense up. She stayed relaxed this time.