Visible crew/equipment: After the looter is helped into the squad, just as Roy gets into the driver's seat, the reflection of camera equipment becomes visible on Squad 51's vent window (not to be confused with Roy's arm or the reflection of the red wing mirror).
Visible crew/equipment: When Roy and Johnny are with the teenage girl who OD'd, Roy walks over to the bystanders, and when he speaks to the mother and daughter, the perpendicular actors' marks are visible on the ground where they stand.
Visible crew/equipment: When the truck driver who felt like his head exploded is in the treatment room with Early, Brackett and Dix, as the camera passes behind Brackett it casts a moving shadow along the two walls.
Visible crew/equipment: When Roy walks into the ER with the man who attempted suicide three ways, due to the low angle of the camera we can see part of the unfinished ceiling of the ER set, near the nurses' station.
Nurse's Wild - S1-E7
Visible crew/equipment: After rescuing the man trapped at the chemical plant, DeSoto and Gage walk into Rampart and when Gage walks up the hallway with Ellen, the actor's black tape mark is visible on the floor, where Gage stops to flirt with the nurse.
Nurse's Wild - S1-E7
Visible crew/equipment: When Roy and Johnny are at the house with the unconscious woman and barking dog, the set lights are reflected in the deputy's helmet.
Visible crew/equipment: When Brackett and Early are in Rampart's staff lounge discussing J.P. Dumont, Brackett agrees to let Early use his charm in the case, and when Early stands up an actor's small T-mark is visible on the floor, where Brackett was standing moments earlier.
Visible crew/equipment: When John and Roy are tunneling through to the little girl trapped in the hole, they're in the second larger hole that has been shored up on all sides with wood (to keep it from collapsing), but when Roy points the chrome flashlight down the lateral hole Johnny's digging in, we can see in its reflection that the fourth wall doesn't exist, where the camera and lights are located.
Visible crew/equipment: While Roy and John are on scene with the "car over cliff" Johnny heads down to the car too quickly, and when he ends up falling his mic transmitter and cable slip out from their hidden area, and become visible on the front of his shirt.
Visible crew/equipment: When Early and Brackett try to deal with the elderly group who want to see their friend, as the group walk away toward the waiting room, two actors' T-marks are visible on the floor, one of them is at Dixie's feet, the other beside her.
Visible crew/equipment: When Squad 51 is dispatched to the man trapped in the freezer, Johnny and Roy get into the squad, and the reflection of the large set lighting can be seen on the passenger door and vent window.
Visible crew/equipment: After Squad 51 arrives at the scene of the parachutist who's stuck in the tree, when Roy tells dispatch to have an engine respond to their incident, the reflection of array set lighting is visible on the squad's surface.
Visible crew/equipment: After the man with trichloroethylene poisoning is hosed down and loaded onto the ambulance, while Roy's on the Biophone with Rampart, John's uniform jacket is pulled open with his hands on his hips, and we can see the outline of his mic transmitter in his shirt pocket with the wires coming out of the pocket.
Visible crew/equipment: At Rampart, when Dixie walks over to Dr. Brackett, who stands behind the station, the tape mark is visible on the floor, just before she steps precisely on it.
Visible crew/equipment: A few shots after Johnny informs Brackett of the victim of the radiation incident, there's a shot of the ER with two orderlies pushing a gurney towards the camera, and the two actors' tape marks are visible on the floor at the bottom of the screen, just before Brackett and Dixie stop there, when Brackett tells Dix to notify the radiation security guard.
Visible crew/equipment: When the babysitter runs into Rampart carrying the boy, both Dixie and Brackett are standing at the nurses' station talking and an actor's white T-mark is visible at Dixie's feet.
Visible crew/equipment: Just as Dixie lets the unconscious teenager's parents walk into the ER treatment room, the actor's T-mark is visible on the floor behind Gage's legs, a moment before Brackett stands at the mark.
Visible crew/equipment: When Brackett, Dixie and Early are working on the unconscious little boy, once Brackett says to go with the pacemaker, multiple black T-marks are visible all over the floor - three under the gurney and one near the cart. Another actor's white tape mark is visible under the gurney (partially blocked by the green oxygen tank), where both Early and Dixie stand at different times.
Visible crew/equipment: When Squad 110 pulls up to Chopper 14, the reflection of the reflector screen is visible on the squad's surface, and when all the guys climb into the chopper, the reflector screen's reflection is visible again.
Visible crew/equipment: When Roy has trouble sleeping in the middle of the night, he gets up, and when he goes to the bathroom sink, there is a fully dressed crew member whose reflection is visible in the mirror, as he moves around and looks through the door window towards the actor. Then 51's tones drop, and in the next shot we see that all the other guys of Station 51 have been lying in their beds, before getting up and putting on their turnouts.
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.