As Emmett Clayton steps into an elevator at the hotel, his shoes are light tan loafers, suede-looking, almost matching his suit. When he gets off the elevator, his shoes have been transformed to shiny black leather with silver buckles.
After Linda packs Dudek's medications into the bag, she holds the handles with the strap between them when she closes it and walks through the door of the bathroom. In the wide shot of her walking through the door, the bag is latched properly.
Clayton doesn't have his ear piece in when walking down the hall to enter the doctor's room. He has it in while talking to Columbo in the lobby before entering the elevator and as he enters the doctor's room once Anton has left.
The list that Clayton is re-creating from memory shows digitalis and digoxin as the first two items on the list. These two are the same thing, and if a person was to take double a life-saving dose, it would be fatal.
It is not harmful for diabetic patients to eat garlic. Garlic can actually benefit blood sugar.
Hospitals do not allow patients to take their own medications.
While waiting for Dudek, Clayton's clock reads 3:29. He has the black pieces and hasn't made a move yet, so it should be 0:00.
During the drive when Columbo picks up Clayton from the hospital, Clayton says "I stopped to pick up a new transistor for my hearing aid, it went out on me last night." He should have said battery instead of transistor-- if a transistor in his hearing aid "went out" then he needs a whole new hearing aid since transistors are not replaceable by the average person.
Clayton who is British tells his Russian opponent Dudek that he had a lover's quarrel with Dudek's assistant and wants to send her a note of apology. He asks Dudek to write it for him in Russian. Clayton then claims Dudek wrote it to him and slid it under his door but he neither reads or speaks Russian.
When Emmett Clayton is playing a simultaneous exhibition, he is so rattled by Columbo that he loses a game in 2 moves. The moves appear to have been 1.f4 e6 2. g4 Qh4 checkmate. This is known as " fool's mate", and no grandmaster, no matter how rattled, would ever lose this way.
In the murderer's hotel room are several members of the crew in the mirror.
As Emmett Clayton sneaks into Dudek's apartment for the second time (to mess with the medication), he sneaks past a room where there are two figures: an older man with mustache in a white shirt and a woman sitting on his front left side. The apartment is supposed to be empty.
Dudek's clock reads 3:52 while they are waiting for him. In a chess tournament each player has 90 minutes for the first 40 moves. If a player is late and doesn't arrive within this time, the match is over and the opponent is the winner. So they wouldn't be still waiting after nearly 4 hours.
As Columbo and his sergeant are examining the crime scene at the trash compactor, they both put their hands on the railing being dusted for fingerprints and palm prints by the print technician only inches away.
Clayton tapes the lock to Dudek's room so he can sneak back in later (after the cleaning person pulls the door shut behind her). But the lock is a deadbolt, not the spring-loaded self-locking type. When he returns, you can see the cleaner didn't even try to lock the door from the outside with a key (the only way she could have locked it). Either way, if she had locked it the deadbolt would have just snapped the tape. The taping makes no sense.
About 3/4 mark: When Emmett Clayton demonstrates his excellent memory to Columbo, he says, "Sir you aren't a champion you're a" which he claims was Columbo's first statement to him, BACKWARDS. What he said, then, would have been, "A you're champion a aren't you sir" (but what Columbo had said was, "You're a champion, aren't you sir?"
Tomlin Dudek and his entourage clearly are supposed to be from an Iron Curtain country. Yet Dudek's aide/physical trainer carries American Tourister luggage, as seen when he and Linda leave the hotel with Dudek's medication.