In the episode "J. Digger Doyle", the ROBIN-2 car is driven back to the Masters estate by a random man who says Higgins resigned from Robin's service, purchased a one-way ticket to London, and gave the man the keys to drive the car back to the estate. The man gives an accurate description of Higgins, but Magnum and company suspect that the man had talked to an imposter, and that the real Higgins may be in trouble. Rick chimes in thusly:
Magnum, locked out of the guest house (again...), trying to pick the lock as Zeus and Apollo approach.
Magnum: Look at the lock, don't look at the dogs; look at the lock, don't look at the dogs... You looked at the dogs!
Magnum and Rick describing Rick's sister to a cop. Magnum is describing a Good Bad Girl Rick a Purity Sue. And the cop is wondering if they are talking about the same woman.
In the episode "Double Jeopardy," Magnum takes part in a movie shoot as a stuntman for an actor whose character gets beaten up. Later, Magnum and Higgins watch the dailies with the producers, and Higgins is seen roaring with laughter at the footage of Magnum getting his ass handed to him.
Higgins: It's so close to reality!
Luther Gillis' constant referring to Artie Keanu as "Artie Canoe" in his first couple appearances, so much so that even Magnum screws it up at one point when confronting Artie's wife.