In the opening sequence, Kenneth Baxter can be seen in the background raising a cigarette to his mouth and putting it between his lips. They then cut to a closeup, and he's still raising the cigarette to his mouth.
When Doug removes the glass container of "volatile spirits" from his office closet, the label reads "mineral spirits." However, when a closeup of the container is shown, it says "Volatile Spirits." This was done due to the censor not wanting the name of an actual accelerant to be used.
During Burger's examination of Hilliard, Devoe, and Roland, closeups show a makeup smudge on the front of his collar where his neck touches his collar.
James Hing implausibly wears rather shabby work clothes to the bank while cashing a check for Mr. Baxter. He wears the same work clothes while setting fire to the Baxter mansion in the next scene. Presumably both scenes were shot on the same day, and the production was too rushed to allow actor Benson Fong a change of costume.
Several times, the words "volatile spirits" are substituted for "mineral spirits" due to censors not wanting to have an actual accelerant mentioned on the show. Doug says it twice and Winnie also twice when they are in his office and first find the glass container of the spirits. Perry Mason says it once when he is interviewing Hing after his arrest. When Mr. Nelson is being questioned on the stand by Hamilton Burger, he says it twice (the spirits were bought at his store) and Burger once.
James Hing is a beneficiary of a will. He brings it to Mason for advice. He leaves the will with Mason for further examination. Later in the episode Perry talks to a banker and asks who is the executor of the will. The banker says that he is. Mason should have known this because he had the will previously.