I'm not sure determinism alone is sufficient for proper attribution.

This presumes "chunks" are the source. But it's not easy to identify the propositions that form the source of some knowledge. In the best case, you are looking for an association and find it in a sentence you've semantically parsed, but that's rarely the case, particularly for medical histories.

That said, deterministic accuracy might not matter if you can provide enough context, particularly for further exploration. But that's not really "chunks".

So it's unclear to me that tracing probability clouds back to chunks of text will work better than semantic search.