Complex sentence: Levinson suggested ending the episode with the detectives walking back to the surface, then feeling the hum and vibration of the train starting back up under their feet; this suggestion, however, did not appear in the final episode.
Split into simpler sentences: Levinson suggested ending the episode with the detectives walking back to the surface, then feeling the hum and vibration of the train starting back up under their feet. This suggestion, however, did not appear in the final episode.