That happens to some degree in every scene, usually on a second pass after I've written down the bare bones of What Happens Next*, and my mind is freed up to see layers and nuances, or to catch dialogue and motives I hadn't considered on the first pass. To get deeper into the viewpoint character's mind, and consider more closely what the secondary characters are feeling and thinking so I can show that in their speech and body language.
*The first pass at a scene is a matter of getting down the stage business and basic emotional push and pull between the characters. Sometimes this comes out choppy and rough, little more than my initial, present tense outline turned past tense, and transformed into a semblence of modern English grammar.So yesterday I finished a new chapter that bridged two older chunks. Now another chunk awaits another bridge. I've looked it over this morning and plan to begin work on it tomorrow (when I know a scene or chapter has to accomplish several things, and there's no absolute certain way in which it much be done, I tend to need an afternoon and a night's sleep for my brain to mull over the best and most concise approach).
Hopefully it will be a short chapter, and then I'll snowball into the final acts of this crazy long book.