Visible crew/equipment: At the scene of the traffic accident, after Captain Stanley tells Johnny and Roy that the victim may have a fractured pelvis, just as Johnny places the Biophone on the roof of the car the camera's angle tilts down to face the victim, and we can see the reflection of the cameraman/crew member on the car window.
Visible crew/equipment: When Squad 51 is dispatched to 'man unconscious possible heart attack', while en route, two shots after Roy says "It's gonna be a long run," the reflection of the squad is visible on windows they drive past, and we can see the reflection of a crew member who's standing on the back of the moving squad. Slow motion is not necessary to see this. However, if you're into slo-mo you can catch it again later, when John and Roy head to the traffic accident victim.
Visible crew/equipment: During the rescue at the jail, while Roy is hanging on the line, the outline of the mic transmitter is visible on his shirt at his left side.
Visible crew/equipment: When Johnny is kneeling on the sidewalk beside the woman who fainted, the outline of the mic transmitter can be seen at his left side, above his belt.
Visible crew/equipment: When Station 51 is dispatched to the plane crash, we hear Captain Stanley respond, "KMG365," and as he walks in front of the engine the partial reflection of the cameraman is visible on the windshield, right in front of Mike who's sitting in the driver's seat.
Visible crew/equipment: When Roy and Johnny load the woman who fainted onto the ambulance, the curly haired attendant gets in the back with Roy and the patient, but en route Roy is alone with the patient, and when Roy tells them to pull over we see the silhouette of the curly haired attendant sitting in the front passenger seat. Then when the ambulance pulls over, only the driver is in the front.
Visible crew/equipment: When Roy's in the ambulance with the woman who fainted, he gets permission from Brackett to leave the TKO patient, so he and John can join Engine 51 at the traffic accident nearby. When the ambulance pulls over, the reflection of array lighting can be seen on the surfaces of both the ambulance and Squad 51.
Visible crew/equipment: At the scene of the plane that hit the building, after the explosion, when Foam 10 arrives there's a closeup of the firemen using the foam tubing, and behind the doorway one of the 'firemen' kicks the foam tubing, but notice that he's not really a fireman, he's actually a crew member who's wearing a turnout coat, though he's also wearing jeans and work boots.
Visible crew/equipment: When Mr. Laurents visits Station 51, as the guys stand up the actor's T-mark is visible on the floor, between DeSoto and Chet, just before Chet promptly stands at his mark.
Visible crew/equipment: After Johnny and Chet begin their arm wrestling, when dispatch drops the tones, there's movement at the front seats of Engine 51 where the camera is located, while Captain Stanley is at the radio base station and Mike is putting on his turnout.
Visible crew/equipment: At the structure fire at an abandoned building, when Engine 164 arrives, we can see the reflection of the location's array lighting in the driver's side window.
Visible crew/equipment: After Johnny reads the note from Mr. Laurents, which he left with the package of money in the fridge, Captain Stanley walks over to the counter, where the actor's T-mark is visible on the floor.
Visible crew/equipment: When Roy is in the ER due to the dizziness, two actors' T-marks are visible on the floor near the door, where moments later Dr. Bracket and Dr. Early stand before leaving. Additionally, Dr. Early's mark (during The Exam) becomes visible when Dixie shifts her position, just as Dr. Bracket asks, "Any pain here, Roy?"
Visible crew/equipment: When Mr. Grady (self-defense instructor) is in the ER, being examined by Dr. Brackett, there is a visible T-mark on the floor behind Gage.
Visible crew/equipment: After Station 51 is dispatched to the fire at a singles club, when Engine 51 pulls into the parking lot it and then turns around, the reflections of multiple array lighting can be seen on the engine's surface and Mike's window when he opens the door.
Visible crew/equipment: At the site of the hang gliding accident, when Captain Stanley and Marco are pulling the stokes up the side of the cliff, the outlines of the lav mic transmitter and wire are visible on the back of Cap's shirt.
Visible crew/equipment: After Brackett examines the self-defense instructor, when Brackett speaks to Mrs. Grady in the hallway, the outline of the mic transmitter is visible at the front of Roy's shirt.
Visible crew/equipment: Near the end, when Johnny's walking from the locker room to the kitchen and checking his watch, the bulging outline of the mic transmitter is visible on the front of his shirt.
Visible crew/equipment: When Roy and John are treating the self-defense instructor, the outlines of the mic transmitter and wire are visible at the side of Roy's shirt.
Visible crew/equipment: When the self-defense instructor is teaching the class, the outline of the mic transmitter is visible on the front of his shirt, particularly when he tells the ladies, "Here's a little bit of judo that you'll all be learning too."
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.