At the end of the show, Michael Crichton's surname is misspelled ("Chrichton") and remains so for the duration of the sixth season.
This episode dedicated to the memory of Chris Salamunovich.
Goran Visnjic, Michael Michele and Paul McCrane join the cast with this episode. Visnjic and McCrane are the first male additions to the series' main cast - all new cast members in the first five seasons were female. This is the largest simultaneous cast expansion in the history of the show, with three additions (two of which did not guest star previously).
Goran Visnjic (Luka Kovac) and Alex Kingston (Elizabeth Corday) both went on to appear in Dr. Who.
When Chris (the rude man from the train) crashes, Dr Benton asks for a scalpel to perform a thoracotomy. You can clearly see the 'cut' has already been made and that Dr Benton isn't cutting anything.