I never considered Dr. Mayfeild wanting Harry to survive it's an interesting thought. He may have gotten addicted again but he would also have remembered that someone came into his apartment and shot him up. I think Mayfield gave him a lethal dose, he thought his reputation would prevent anyone from suspecting him of anything. Harry overdosing on morphine he got from Sharon was what he needed, maybe they would then suspect Harry of killing her and now he was dead so case closed.

Back when I was watching Columbo for the first time, this is when I learned that lack of clues made a murder more suspicious not less easy to solve. No finger prints creates raised eyebrows and something more to think about.

This is the only time we ever see Columbo use anger to try and shake a suspect, I wish he had done this a few more times. When he slammed the pitcher down on Mayfield's desk it caught me way off guard, this was a nice touch I wish would have been used again. It would have been especially memorable if he did that toward one of Jack Cassidy's characters, Or if Columbo would have done that to Mark Halpern when he was in his office now that would have been a scene!

Bam!! Columbo slams a paper weight down on Marks Halpern's desk looks him right in the face and accuses him of murder. Awsome!

I'll have to admit, for many years I didn't even realize that Harry had actually died, since (if I remember correctly) there isn't any explicit mention of it. Of course, it's implicit in the context of the story that he died, which just struck me fairly recently. Also, if I'm not mistaken, with Harry being murdered, that makes Dr. Mayfield the only triple murderer (well, one is an attempted murder) in the series. Of course, Ruth Lytton in "Old Fashioned Murder" had three victims, but only two were a part of the present story.
And I agree with you, J, the scene where Columbo shakes up Mayfield is extremely effective. I like how you worded it, too, with Columbo USING anger against Mayfield. When he loses his temper with Milo Janus in "Exercise in Fatality" (which is a great scene, too) it seems less that he's using anger as a tactic, and more that he's genuinely indignant toward Milo. He supposedly used anger against Joan Hudson in "Prescription Murder", too, but that scene for me just comes off as disturbing and out-of-character, unlike the scene with Mayfield.

J, There are three more episodes I have seen Columbo display anger: "An Exercise In Fatality", "Mind Over Mayhem", and "Murder Under Glass". I will not spoil it by pointing them out unless you want me to.

Another is DEADY STATE OF MIND. I've never been fond of that line directed at Dr. Borden - "No, I'm asking YOU!"
All right, it isn't actually SHOUTED at her, but it is unpleasant. It's a little like the big moment between Columbo and Joan Hudson, but even less called for, since this person isn't some accomplice.

Grant, I meant the episode you mentioned instead of "Mind Over Mayhem". Sorry

That's understandable. I confuse those two titles constantly.