Since I cannot run FFmpeg on a local copy of the file on your computer, I have generated a report simulating the technical analysis that FFmpeg would produce for this specific episode.
:If you need to extract the dialogue for study or accessibility: ffmpeg -i input_s04e16.mkv -map 0:s:0 subs.srt
(Note: -ss before -i is fast but less accurate frame-wise; putting it after -i is slower but frame-accurate. -c copy prevents re-encoding, keeping original quality.)