As it turns out later, the staged traffic accident turns out exactly as planned. Therefore, Prescott running to Jonson saying "You fool, you bungled it" makes absolutely no sense.
When Perry arrives at Selkirk's place with Claire, the shot of Mason's car shows that Perry is alone in the car. In a later scene with Della, Perry is driving a different, newer model car. The scene with Della was filmed for this episode while the earlier scene was taken from the first season episode "The Case of the Vagabond Vixen" which explains the absence of Claire and the older car.
When Frank Fettridge emerges from hiding in the other room, Frank says, "Yes, I know about him. It's Perry Mason, Lorraine." The girlfriend's character's name is Loretta, not Lorraine.
A microphone is visible in the lower left corner during the scene when George Andrews is helping Loretta Harper/Beatrice Cornell to his car after the accident.
This episode is based on Erle Stanley Gardner's novel TCOT Gold Digger's Purse.
For those who are curious, the Uniform Code of Military Justice allows military personnel charged with crimes to retain civilian attorneys as legal counsel in military judicial proceedings.
While Mason is cross-examining Lt. Tragg, we see Paul Drake's unoccupied chair next to Mason's. However, as Perry returns to his seat, Paul's chair has moved and is now blocking the swinging gate leading to the witness stand. The chair then moves back next to Mason until Perry gets up to cross-examine Lois Gilbert when it again is blocking the gate. Then the chair again returns to its normal position where eventually Paul enters and sits in it.