Regina Mills wasn't the type of person to be intimidated by others. She was the one who dealt out the intimidation. The entirety of Storybrooke feared her, except maybe you and Gold. And Regina relished in that fear, that control that she had always had. But when Emma got here, that control wasn't so complete.

It was clear that Regina saw Emma as a threat. Not because she was a force to be reckoned with - Regina was more than confident in her abilities to deal with the Sheriff. But it was her very presence that worried her. She was near Henry. Regina couldn't lose Henry. So when Emma outright told her she was "taking her son back", Regina didn't know how to deal with that.

That was why her voice seemed choked up on the phone when she called you. It wasn't a state you often heard her voice in, which only served to worry you. When you got to her place, she explained it all to you.

"She means it. I don't know how to explain it, whether it was her tone, or the look in her eyes, I just-"

Regina cut herself off, shaking her head. She couldn't believe she was getting this worked up over Emma. Even so, her hand raised to toy with the charm around her neck, as it had when Emma had threatened whole-heartedly to take away her son. Henry was her everything, her happiness, her light. And he was slipping right through her fingers.