Continuity mistake: In the scene where the gang are chasing after the two kids, it is raining and the street is wet. They stop chasing and turn around when they see a police car go by. In the first shot of the police car, the street is completely dry. (00:05:45)

MacGyver (1985)
1 continuity mistake in Blood Brothers - chronological order
Starring: Dana Elcar, Richard Dean Anderson
Continuity mistake: During the car chase through the desert, the rear view mirrors on both cars disappear and reappear repeatedly.
The Eraser - S2-E2
MacGyver: Dreams are important, otherwise sleep is just eight hours of nothing.
Trivia: As the series wore on, Dana Elcar began going blind as a result of glaucoma. This condition was eventually written into his character, as well.
More questions & answers from MacGyver





Answer: Late one night, Geoffrey used a covert listening device to overhear David explaining his barricade device to Janet which is how he figured it out.
How do we know Geoffrey really did use a covert listening device? They didn't mention him using one.
There was a scene of him using it when David told Janet about his barricade.