As Strattera no doubt knows, the idea that the world is riddled with underground tunnels is a staple of conspiracy theories. (See, for example, this site, or this one.) And it’s important to remember that not only was there an underground passage, Flyss’s observations together with evidence compiled by Stephen suggests that there was an underground dwelling stocked with provisions on the spot, and an aged man living there. Underground dwellings are another such staple. My conspiracy theory leanings are, for good or ill, becoming stronger with each revelation in this case.
Kate has convincingly hypothesized that the man was a Hafeem, as it is difficult to imagine any other reason why someone of his apparent age would live in such a way.
But that begs the question on why the Bounty Hunter kidnapped him. Furthermore, given the apparent connections between the BH and Laughing One, one naturally wants to ask the latter for an explanation.
But I suspect that the actual reason he sent Flyss back to the farmhouse is that he wants us to deduce the answer to that. — Glenn
[Addendum: In the comments section to this post, Laughing One seems to be stating: "Bingo!"]