In the establishing shot of New York City, the Empire State Building can be seen in the background. This episode originally aired a few months after the episode "Terror in New York City" (where the Empire State Building collapsed when it was being moved), so the events in this episode should have taken place before "Terror in New York City".
Thunderbird 2 transports the Mole in Pod 3. When The Mole exits the Pod, there is a sign inside the pod that says "Thunderbird 2 - Pod 5".
In the opening scene at the casino, the rogue croupier at the Duchess of Royston's roulette table is voiced by Matt Zimmerman. When the same "croupier" calls out "18 red", he is voiced by Peter Dyneley (the voice of the croupier at Lady Penelope's table).
When the croupier at the Duchess' table calls out the phrase "Rien ne va plus" (French for "No more bets"), he pronounces "Rien" incorrectly - he pronounces it as "RINE ne va plu" instead of "ree-EN ne va plu".