Anything you can conclude about the mind is based on a mental model, so nothing that suggests discriminating self from mind can be true. You might say that mind is just an appearance in consciousness because consciousness is the apparent window through which mind knows itself, and going on in this way you might also experience that consciousness can have no boundary, but again this assumes that consciousness is a thing apart from its mental model. In relation to mind consciousness is less presumptuous. It sees itself anamorphically thinning out to nothing, to unconsciousness, it sees itself rooted in mind like a plant - its tendrils going on into dark intimacy with hidden currents of energy and form. Perhaps the question should, what is the form of unity that pertains to the mind? A unity that has no analogy among appearances.