I think if she were there for PR purposes, that would be more substantial than what she's currently doing. She's the type who sabotages donation possibilities.
I wish Murphy had more respect for the organization that is not only a source of income for her and her parents but is also a place of employment for other people. I can't imagine having to work with her.
I think Murphy was reacting out of emotions and looking for someone to blame. Also, she resents that Max didn't tell her. It seems like she doesn't fully grasp understand how dangerous this drug dealer lifestyle is and that, even though Max is not physically on the street selling drugs, he's still involved in it.
Something bothered me about Vaness in that scene but I couldn't figure out what - you just nailed it.