Complex sentence: As Rick sits in silence with a blank stare on his face, Negan drives through heavy fog and smoke, but shortly stops where a herd of walkers have gathered and a fog has consumed everything.
Split into simpler sentences: As Rick sits in silence with a blank stare on his face, Negan drives through heavy fog and smoke. Negan stops the RV where a herd of walkers have gathered and a fog has consumed everything.