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.
Visible crew/equipment: When the doctor shows up at the house of the man who kicked in his TV, as the camera moves back, the top of equipment (presumably the boom mic) is visible and moving in the reflection of the mirror on the wall.
Visible crew/equipment: When Johnny and Roy are working on the man who is unconscious due to electric shock, the bulging outlines of the lavalier mic transmitter and wire are visible on the back left side of Johnny's shirt.
Visible crew/equipment: After the ambulance transporting the cardiac victim is involved in a traffic accident, when Roy contacts the dispatcher about the accident, the reflection of location set lighting is visible on the back window of the ambulance.
Visible crew/equipment: After everyone worked together on the cardiac arrest while the visiting administrators watched, at the nurses' station, when Johnny pours the coffee for himself, which Roy promptly takes, the reflection of set lights and equipment are visible in the very reflective chrome coffee pot.
Visible crew/equipment: When Roy drives off in the squad just as Animal Control shows up at the store with the tiger, we can see multiple reflections of array lighting on the vehicle and also the store's windows across the street.
Visible crew/equipment: When the Animal Control guy and the officer are in the grocery store, a few shots after the tiger jumps over the counter, the hand of a crew member (presumably the tiger's trainer) is visible behind the boxes holding a piece of food, as the tiger walks toward it (away from the camera).
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.