But this raises anew the question about the virus that conveys endless immunity from disease and aging - who or what brought the virus, or, how did it originate and come to humanity? Actually, this question has been with the series all along, but now it's looming in importance.
Let's rule out time travel, because, much as I love it and write it as an author, we've seen no evidence of it at all on Helix. We had no idea when hapless Gunnar was infected and made immortal, only how long he'd been in solitude. But we now know that Hiroshi became immortal some 500 years ago. This means the virus cannot be a creation of our current technologies, or a technology that was developed somewhere in the world that is slightly or more advanced what we now do in our laboratories.
But if not a deliberate infection via time travelers from the future, what then? There are several possibilities: the virus naturally emerged, the virus was brought here by aliens, the virus was the result of some intentional or unintentional human experimenting with corpses, diseases, blood, whatever 500 years or more ago.
Although I wouldn't rule out the third possibility - and, in fact, prehistoric gene splicing plays a significant role in my novel, The Silk Code - it would be pulling a rabbit out of a hat for Helix.
So that leaves natural occurrence or aliens. And that also, again, points to the question about the Ilarians: are they humans tranformed by the virus, or are they aliens? Presumably we'll find out more next week.
In the meantime, a farewell to Daniel/Miksa, whose noble sacrifice was one of the best scenes in the series.