This is what I refer to as a Mary Redemption Moment. She's been catty with Hanna from the beginning, and couldn't wait to run her out of Charterstone. Now we learn that she really does want to help Hanna, whom she considers to be her friend. If she had actually spoken the words, "I want to help you, friend," we would have doubted her sincerity based on our review of past interactions, and so the author has placed them in a thought bubble because Mary never lies to herself. But who would actually think this kind of thing without actually saying it?