Dr. Mayfield has no name plaque on his office door when Columbo first walks in. However, at the end, when Columbo is in Mayfield's office, there is a 'DR. MAYFIELD' plaque on the door.
When Columbo first visits Dr. Mayfield in his office, his hair is a mess. When they both leave the office and talk again in the hall, Columbo's hair is no longer messed up.
The three items on Dr. Barry Mayfield's desk in his office change position, depending on camera angle.
(at around 1 min) In a closeup of Sharon's roommate Marcia reaching for a tissue in her bag, the bag is opened to show the buckle up by her breasts. In the next (wider) shot, she's still struggling to open her bag.
When Marcia opens her apartment door, she says to Columbo, "Here we are", they are outside; it's an external front door. In the shot of the door opening from inside the apartment, they are in a hallway; it's an internal front door.
During Dr. Hidemann's first operation, Dr. Mayfield twice asks about the patient's pressure, but the anesthetist only nods. Standard procedure would be for him to verbally respond to the surgeon.
Taking blood pressure is bungled twice. First, Dr. Hidemann takes his own pressure with his arm bent double, which would make it impossible to get an accurate reading. The second time occurs when Dr. Mayfield is taking Hidemann's BP post-op, and he has no stethoscope.
Despite performing open heart surgery, Dr. Mayfield never has blood on his gloves.
The surgeon (twice) stitches a part of the valve, with many more sutures to do (held by the assistant) and just says "he's all yours": on top of finishing to stitch the valve, the patient still needs to have his sternum and his chest (including the skin) stitched.
When the surgeon asks for suture, he is handed a pair of forceps with no thread or needles clamped in it.
Columbo tells Dr Mayfield that everything fits, a hypodermic needle had been found in Harry's room, but one would not use a hypodermic needle for intravenous injections.
It is possible that Columbo did not get the proper term to describe the needle, he has shown that he needs to be explained the difference between a resorbable and a non-resorbable suture material.
It is possible that Columbo did not get the proper term to describe the needle, he has shown that he needs to be explained the difference between a resorbable and a non-resorbable suture material.
When Columbo is talking with Marcia Dalton, the roommate of the victim, Peter Falk accidentally calls her, "Miss Talbot", which is the name of the actress, Nita Talbot.
Dr Mayfield holds Harry's wrist and forces the needle in the elbow (it goes in with a jolt). This is a terrible way to find and inject drugs in a vein.
When walking on the pier (a long/wide shot with various people walking), there are three extras walking behind and away from Dr. Mayfield (Leonard Nimoy) and Marcia (Nita Talbot). The lady in the middle of the trio turns her head and looks back at the two star actors. She keeps her head turned for a couple seconds before looking straight ahead. This is a mistake if she was a hired extra. Although, being a public pier, it's possible the trio were random people, with the head turn caused by a recognition of Nimoy.
When Dr. Mayfield pulls cans out of the cupboard at the nurse's apartment, some of them sound empty, even though they haven't been opened.
When the morphine is found under the bathroom sink in the victim's apartment, the water supply pipes and fittings seen are obviously galvanized. Water supply pipes in residential building are either brass pipes or copper tubing.
As Columbo walks through the zoo to meet Harry Alexander, the background voices and sounds repeat several times and are clearly on an tape-loop.
When Columbo enters the apt of Sharon Martin's roommate Marcia Dalton, right after Marcia says "well, here we are" -- to the left of the screen you can see some camera/lighting equipment for a brief moment before being pulled out of the shot.
Just after the first surgery, the surgeon and the nurse remove their hats and masks still wearing their soiled gloves. Dirty, blood-stained gloves are (very logically) always the first piece of equipment to be removed.
An anesthesiologist would never remove the orotracheal tube so quickly without the patient showing signs of breathing by himself, which usually takes several minutes after the drugs have been stopped.
Dr Mayfield is touching his hair with his soiled surgical gloves on.
Dr Simpson listens to Dr Hidemann heart with his stethoscope the wrong way around in his ears (the bits are meant to be positioned towards the front, not the back as done). Dr Hidemann then takes the scope from his colleague and turns it around before repeating the mistake.
Just after the first surgery, the surgeon and the nurse are rubbing and massaging their own necks still wearing their (supposedly) soiled gloves.