Absently swatting mosquitos, the Diver looks out over the swamp to the south. He stands by the three cairns to the southeast. He sleeps there, by the cairns, that night.
It's there - at some late hour - that he hears the faint sound of machinery slowly rumble to life, and then the distant purr of water coursing into a shallow basin. The crescent moon shines enough light to show ripples form across the surface of the floodland. Looking higher he spies several small but sure lights very far away to the south, above the horizon, as if from a row of open windows or portals. They're so small they might easily be mistaken for stars in strange alignment. They even twinkle, in a way: the light breeze moves unseen branches, causing some lights to fade or black, then reappear, then dim again.
The Diver wipes his forehead of sweat (it's an unbearably hot night) before falling back into a ball in the tall grass by the creek.
Next day:
Well, the Hippocratic Oath doesn't necessarily prevent me from taking all life. I can't purposefully harm my patients. Or bring harm to others on behalf of a third party.
Except in Oregon.
Except in Oregon, you're right.
The Diver asks if there's anything else that might prevent them from dueling.
Not that I can think of, no.
Maybe you're not thinking hard enough.
The Doctor shrugs.