Robert Duncan McNeill helped refine the episode's conclusion. "I helped them rewrite the episode's final scene. I did not feel the original story ended very well. I was pleased because I got to have some input into how to resolve the story."
In 2003, Brannon Braga said, "It's a terrible episode. People are very unforgiving about that episode. I've written well over a hundred episodes of Star Trek, yet it seems to be the only episode anyone brings up, you know? 'Brannon Braga, who wrote 'Threshold'!' Out of a hundred and some episodes, you're gonna have some stinkers! Unfortunately, that was a royal, steaming stinker."
In the shooting script of this episode, the eponymous shuttlecraft that breaks the warp 10 barrier is named the Drake; however, a shuttlecraft of that same name is destroyed in Non Sequitur (1995). The eventual name of the shuttlecraft here was the Cochrane, named after Zefram Cochrane who broke the warp 1 barrier.
Tom Paris was used as this episode's central character because the writing staff believed he had become underused as the first season had progressed.
While Tom Paris is in sick bay, he mentions that B'Elanna Torres doesn't cry. In Star Trek VI: The Undiscovered Country (1991) it is mentioned that Klingons have no tear ducts.