Dedicated to the memory of Mace Neufeld (July 13, 1928 - January 21, 2022). Neufeld was a producer of all five Jack Ryan films and an executive producer of the first two seasons of this show.
The ringtone you hear in minute 40, when Ryan calls Greer and Wright on the conference phone is the same ringtone as used by the Counter Terrorist Unit (CTU) in 24 (2001). It is very well-known and became sort of a brand of 24 back then.
The establishing shot with the description "Prague Castle" does not show the Hradcany (Prague Castle). The building shown is actually the church "Kostel Matky Boni pred Tynem" (Church of Mother of God before Týn), located on the other river bank of the Vltava river in the old town of Prague. The castle of Prague also houses the presidential office and sits atop a hill above the Mala Strana (lesser town of Prague) and was used in an earlier establishing shot in this episode.