Regina’s favourite past-time pretty much seems to be dropping by the sheriff’s office and taunting whoever happens to be locked up that week. I think it’s safe to assume that she’d be doing that whether Emma tried to stop her or not – she seems to think that as Mayor she gets free reign to be whereever she wants, whenever she feels like it. It is weird that they don’t have anyone to be there when Emma isn’t though, especially when there’s a prisoner in there.