Which goes to show how the Bechdel is a good tool for identifying a bad trend, but not necessarily a checklist for any given story. I have stories where women only appear in passing and others where men do. Then there are stories where the women can only talk to the men because the POV male character wouldn't see otherwise within the scope of the story. Likewise, stories where the women have to talk about nothing but men because not doing so would cause bigger problems (as per your example). Conversely, I saw someone point out that, strictly speaking, the two women could have the most stereotyped conversation about their shopping habits and female children, and that passes. The test has its uses, but I don't think that it works as an individual story measure, no matter the length of the story.

Personally, I interpret the "talk about something other than a man" as "talk about something other than the male protagonist and/or designated love interest." So, Nat and Grace doing an autopsy on a guy would qualify as long as that guy wasn't Nick.