The ride all the way to the restaurant that Damien Park made a reservation for was spent in silence. Because of what Damien and Caleb witnessed a while ago with Katherine and her friends, the atmosphere was quite tense.
When Katherine left, it didn't only affect Damien but also her friends. Compared to him, her friends didn't have any idea as to what happened about her sudden disappearance without telling them where she was headed to or if she was coming back at all. A couple of weeks after she disappeared, Emma came to see Damien and asked about Katherine but all that he could say was that he didn't know. And that was the truth.
Now that Katherine was back and the whole thing about her being the heiress of the Young Family was made known, a lot had changed. It was understandable for Emma to be upset with what she discovered given that Katherine probably hadn't had the chance to talk to her friends yet.