Thanks for tagging me, Buddy!
It is okay to switch between omniscient third, and close/limited third, but it’s best and most effective to split it very clearly from the main text, otherwise the POV won’t feel as genuine for the rest of the chapter.
I’d recommend making a short interlude/aside ‘chapter’ for these mysterious sections you mentioned (e.g. once the character leaves, you can end the chapter, then have a tiny chapter about what they didn’t notice lurking in the shadows there).
If you don’t like miniature chapters, you could also just put a little break (whatever symbol you’re using for time-skips, if you have anything) and add the omniscient section in at the end, perhaps in italics.
Does that answer your question?
Writing Heroes ♦ Writing Hope // janemareeauthor.com.au