Six eulogizing Jamie in Wreck of the Titan when he thinks he’s lost him again by saying “now he’s gone, gone on a journey to the undiscovered country. Without me.”

like. i do think he comes to terms with it a little fast (but I can’t really complain about that, because they get reunited again so soon afterward that he has to accept that he’s ‘dead’ quickly if we’re going to get to hear him mourning him at all - and there’s plenty of opportunities elsewhere in the trilogy to hear the Doctor stubbornly in denial/holding out hope about Jamie’s fate/s) but also - also. huh. im like, still struggling to find the right way to word this because like. That’s gotta be it, right? that’s gotta be the best & most succinct way of putting the Doctor’s feelings on not only losing his companions but death itself too, when you think about it.

Obviously the character doesn’t believe in any kind of religion we would recognize, but while they spend all their lives adventuring through the universe and constantly - no matter how old & experienced they become - stumbling across new and unknown people and places, there’s one place they haven’t gotten to see, but where all of the friends they’ve brought along on their adventures eventually wind up. And of course I think his horribly pained “without me” is a wish to be with Jamie specifically - it very clearly is one in context, since Six is explaining how this particular outing was meant to be a treat for Jamie, who doesn’t remember him at all, because he wanted to recapture “the good old days” when they traveled together on all their adventures - but it also reflects & emphasizes the fact that because Jamie’s gone, they’re both left to their travels, each one as alone as the other.

And the poem he quotes next (Walter Scott’s “Hie Away”) seals it for certain: “Hie to haunts right seldom seen, lovely, lonesome, cool, and green, over bank and over brae, hie away, hie away” - The Doctor evidently envisions Jamie, virtually immediately, as being in a better place (and there’s even something vaguely encouraging, hopeful, aspirational about it, given the imperative nature of the verb hie) - clearly living on in some way, somewhere, some when - but also, crucially, lonely, and on an adventure where the Doctor can’t reach him and join him on.

The way he talks about it, death doesn’t seem to be about an ending to Jamie’s life at all, but rather the separation between the two of them - and in the Doctor’s eyes, that’s just as worthy of mourning all on its own, despite how very accustomed he must be to parting ways with companions in all different kinds of situations by the time he’s in this 6th regeneration.

(idk, even outside the obvious doctor/jamie of it all, I feel like that says a lot about the character’s perspective on both death and goodbyes in general)