Much, much later:
The Professor stood on the beach with two books in his hands, and looked out over the sea. It still startled him, a little, to notice how different the ocean was on this side of the country. After fifteen years in the South Pacific, he scarcely recognized the colors and scents, and even the shape of the waves here on the shores of the Atlantic were alien and a bit unsettling.
He looked at the books he carried one more time. One of them was his own, a bound galley proof of his forthcoming memoir of their experiences on the island. It was based on the meticulous notes he had kept almost from the day of the shipwreck to the day of their rescue. The other was what he still thought was a badly written, badly reasoned piece of pseudoscientific drek; the very study of the Melanesian castaways that he had so contemptuously thrown aside on the morning of his own fateful trip to sea. The story of their descent into madness and unimaginable crimes had been based on the writings—'ravings' might actually have been a better word—of one of the survivors, and the accuracy might therefore have been considered as dubious at best. But the basic story was probably true, and the man's subsequent crippling guilt was certainly real enough. His last sentence, scrawled with a bloodstained hand—'May God be kinder than we ever were'— had never quite left the Professor's memory.
He wasn't really sure what had prompted him to bring these books out here, to the ocean. He wasn't the sort of person for grand symbolic gestures, usually. But he had been here, in New York City, settling some last-minute details with his publisher, and had come across this copy of the Melanesian shipwreck study—entirely by chance— in a used bookshop. And this detour had followed so naturally that he decided not to question his instincts.
"I hope you can all rest in peace," he said quietly, across the sea, across the years. "You… you should know that your tragedy wasn't entirely in vain; if I hadn't known about the seven of you, and of the island madness you faced, perhaps the seven of us, my friends and myself, would have met the same end. You showed us what not to do; perhaps that's some comfort? Either way, rest in peace."
He slid both books into a bag, tied the package firmly shut, and heaved them—the tale of the castaways who had succumbed, the tale of the castaways who had triumphed—as far as he could into the sea. Straightening his coat—again, after fifteen years in the tropics, even a (statistically speaking, quite mild,) New York early spring day felt like the depths of winter to him!—he nodded a farewell to the past and walked away.
OooOooOooOooO
Author's note: Just to clarify things a bit. No, apart from this epilogue, the people described here were not 'our' castaways, all of whom, canonically, survived to be rescued. Ours were far kinder, far more humane, and far luckier than these poor suffering creatures ever were. How much that third condition— luck— informed the first two is anyone's guess, but given that the one episode that addressed the idea of food shortages ended with them collectively deciding that they couldn't bear to kill even a duck, perhaps, both as individuals and as a group, they simply were less flawed than the Melanesian group from 'Ship Ahoax,' who, again canonically, 'destroyed one another.' Whether they were genuinely of sturdier stuff or were simply never pushed beyond their breaking point, this isn't the sort of story I'd want to tell about characters I love, and I apologize to anyone who was unsettled by it.