This is just brilliant, pure and simple. Topher's voice, his innocence and ambition and pride in his work, his hubris in the end, as the Greeks would say. And your descriptions of Saunders, especially at the end with her annoyance...this is exactly how I see their dynamic and it's such a pity we didn't get more of it in the show.

I too see the "old" in Saunders, and I think this could be that the original conception of the character was that she was much older, into her fifties if I recall correctly. But this matches the amalgamation of the old Doctor Saunders into Topher's "new" creation really well, and I love that you've written as such.

Nice job, well done!