Visible crew/equipment: Just after Herbert leaves the station in the morning, dispatch sounds the alarms, and when Roy and John are in the squad while the dispatcher begins talking, there are nice reflections of the camera, reflector screen (in the background), and crew members/cameraman who move around, that are visible on the surface of the spotlight. Additionally, the shadow of the boom/mic is perfectly visible on the windshield as it moves down.
Visible crew/equipment: At the apartment complex fire, after Roy removes the ladder from Engine 51, the Pasadena engine rolls up, and when the Pasadena Captain walks toward Captain Stanley, the second cameraman wearing a brown blazer can be seen standing on the very top of Engine 51 to the left, shooting the overhead footage of the Pasadena engine that was just shown.
Visible crew/equipment: When the guys wake up in the morning and walk into the kitchen, the clear reflection of the camera dolly is visible on the oven glass door as it trucks to the right, when the guys see the empty mouse trap.
Visible crew/equipment: At the apartment complex fire, when Truck 82 raises its ladder, we can see the second floor balcony behind the rig, and there is a crew member wearing a long sleeved blue shirt and white hat, standing in front of the corner apartment, where there should be smoke pouring out, but there is none. The reflection of the cameraman/crew member wearing a white hat also becomes visible in Truck 82's wing mirror.
Visible crew/equipment: When Roy and Johnny are at the laundromat with the drunk man, the bulging outline of the mic transmitter is visible on the left side of Johnny's shirt, over his belt.
Visible crew/equipment: When Charlie, who has smoke inhalation, is placed on the gurney in the treatment room, the actor's white tape mark is visible on the floor, where the nurse stands in a moment.
Visible crew/equipment: When Station 51 is dispatched to the structure fire, just as Engine 51 rolls out of the apparatus bay, the reflections of the location shoot's array lighting and two reflector screens are visible on the side of the engine.
Visible crew/equipment: At the start, when dispatch interrupts the mannequin practice with a structure fire, after the shot of Mike getting into his turnout, as Engine 51 rolls out of the apparatus bay, the reflection of array set lighting and two reflector screens are visible on the moving engine.
Visible crew/equipment: After Squad 51 responds to the 'man unconscious' at the laundromat, while they're en route, when Engine 36 contacts them that the man is in full arrest, the reflection of the vehicle with the camera is visible on the spotlight.
Visible crew/equipment: After Chet tells the guys that they have to get rid of The Mouse, when he says "You don't understand, these things are like rabbits," the moving shadow of equipment, probably the boom mic, is visible on the top cabinet behind Chet.
Visible crew/equipment: After the guys decide to eat lunch before resuming their CPR practice, when Chet picks up the CPR mannequin and walks toward the fridge, the top of the set is visible at the corner, between the fridge and the stove. We can see the top of the set again later, after Chet picks the losing matchstick and has to set the mousetrap himself.
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.