To some degree, she was Lucas Cross' only ally, because, characteristically, she selfishly thought of what he had done for her (he had built their kitchen shelves) and not that Selena would have been traumatized again.
She was partially Lucas Cross' only supporter because, in line with his nature, she thought about how he had helped her (by building their kitchen shelves), rather than thinking about the potential harm it might have caused Selena.