Her eyebrows go up at his use of the epithet 'sweetheart'. She's definitely taking it the way he didn't mean it.

She doesn't say a word in response, though—just fixes him with a look, then glances at the glass doors. She looks down at the keys as she holds them up in her hand, rifles her fingers between them to make them clink against one another, then shrugs with that shoulder.

She fixes that same look at him again. The message should be clear.