The things we leave behind are often thought of as irrelevant- it’s not what we leave behind, but who. I would argue, however, that what we leave can say much about how we lived, which leads me onto my point: what did Jon and Martin leave behind?
By the end neither of them really had many belongings. Martin might’ve had a flat during season 4 but the chances of him keeping it or anything in it when moving to the safe house are quite slim. At the point of moving there they each had all they’d be able to carry on a train to Scotland, not leaving much space for sentimentality.
But when the apocalypse started how much of this would survive? The cabin was the epicentre of the change, would anything there really last in a meaningful way, return to normal? But of course they did take some things with them.
Martin jokes about the bandages turning into snakes, so clearly they’ve had issues with some of their own belongings changing based on domains, so even what was valuable enough to bring with them could have been discarded.
Everything that survived the journey with them would have ended up in their makeshift home of the tunnels under the institute. No doubt it ended up spread out through their shared space, a homely mess, but as we all know there was no chance that it would ever last.
As the institute crumbled and Jon bled in Martin’s arms they were lost, evidence of their existence crushed and broken down to dust; but not all of it. Passed off to Basira, abandoned in a location that somehow survived.
One golden lighter with a spiderweb design, and one tape recorder loaded with the last conversation of Jonathan Sims and Martin Blackwood. Their remains.