Marthe Bernard, Tinny Doyle, appears in the finale of the show with her real-life father Andy Jones, Judge Tizzard.
This is the last episode of the series.
Allan Hawco (Jake Doyle), Mark O'Brien (Des Courtney), and Sean McGinley (Malachy Doyle) appeared together in both the first scene of the first episode of the series and the last scene of the last episode of the series.
In the scene where Leslie Bennett, Krystin Pellerin, and Inspector Pickard, John Kapelos, are wrestling each other for his gun the viewing audience hears a strong gunshot but the viewing audience doesn't get to see who was taken out permanently until the scene when Malachy, Sean McGinley, and Jake, Allan Hawco, are desperately looking for Leslie and find her with a slug in her shoulder.
The gun that John Kapelos used to shoot through Krystin Pellerin's shoulder was filled with blank cartridges and a blood pack was likely sewn into Krystin's jacket.