This is the second and last episode of the entire series not to feature Ron Rifkin as Arvin Sloane. First one is season 3 episode 11, Full Disclosure.
At the start of the episode when on the phone seeking flight manifests from Prague (in non-English), Sydney says "Mr. Nemec assured me it was possible." Andre Nemec is a Senior Producer on the show. The use of the name was likely an inside joke between cast and crew.
Carl Lumbly does not appear in this episode - presumably as Dixon is recovering in hospital after being shot by Elena in the previous episode.