The Box Set: "Slow Horses: Season 3."

Deconstructing Ep. 5, "Cleaning Up."

Last week’s deconstruction of “Slow Horses” delved into the kind of series this is at its heart — a fun, rollicking mystery that makes you, as the viewer, ask a lot of questions. And the questions that were asked last week pretty much got answered in this penultimate episode, “Cleaning Up.”

We focused on Dame Ingrid, of course, because the lengths she’d …