Well, you can't beat this ending for brevity: "Jaromir Hladik died on the twenty-ninth of March, at 9:02 A.M." (13). For a story in which we find such complicated and lengthy sentences, this is a huge contrast, and it definitely packs a punch. It sounds like the kind of phrase you'd find in a medical examiner's report or a newspaper: objective, brief, and free of gory details.
The ending provides an immediate and definitive closure to Jaromir's year of mental activity. It also reminds us that the time that he experienced was completely subjective: while Jaromir was busily working away for a year, no time at all passed in the universe. Jaromir was scheduled to be executed at exactly 9:00 am; by 9:02 am, he's dead. Not even Shakespeare could write a play that quickly.
Oh, also, does this ending remind you of something else? Say, the ending of Jaromir's play? And to think, "The Secret Miracle" is itself a work of literature. So what do you think: does it stop there, or is someone writing Borges' life, too? Hmm, maybe we got a little too deep. But as any good ending should, this one sure gets us thinking.