What is the meaning of “knowledge and vision” in the context of the heartwood sutta?

I am aware of a similar question here: https://buddhism.stackexchange.com/q/31393/2493 However, I would like a deeper understanding of what precisely is meant by “knowledge and vision” in the heartwood sutta and why is its attainment positioned as it is with respect to the other attainments. I feel that I have a good understanding of the meaning of the attainments which precede, and presumably are prerequisites for “knowledge and vision”. Namely 1: gain, honor and renown 2: moral discipline 3: concentration and for the attainment which follows and presumably depends upon it. Namely 5: perpetual liberation but the attainment of “knowledge and vision” itself is frustratingly fuzzy in my mind. I’d like a better understanding of 1: What precisely is meant by “knowledge and vision” in this context? 2: Why is concentration a prerequisite for “knowledge and vision”? 3: Why is “knowledge and vision” a prerequisite for perpetual liberation? My best guess is that 1: Knowledge and vision” represents a level of development wherein one can get to nibbana when needed, but it does not persist perpetually. 2: Concentration is a prerequisite for “knowledge and vision” because seeing the arrow (hard to see) as it enters the heart requires a concentrated mind. Perhaps this is the vision part? Seeing the arrow as it enters the heart enables us to identify precisely where we became self-absorbed in the narrative and thus where the work of severing attachments must be done. 3: “Knowledge and vision” is a prerequisite for “perpetual liberation” because having knowledge of each individual desired sensory experience which the mind is attached to, is required before the work of severing said attachment can begin. Perhaps this is the knowledge part? When all such attachments are severed and no new ones are added, then sustaining nibbana perpetually becomes possible This is a complete guess on my part. Am I close? I am referring to the translation provided by Bhikkhu Bodhi. https://www.suttareadings.net/audio/index.html