Propinquity - S3-E20
Visible crew/equipment: At the abandoned refinery, just after Roy attempts to pull out the man pinned under a tank, but is unsuccessful the first time, when it cuts to Captain Stanley and Chet, who are on the third level hosing the fire through the doorway, at the left of the screen a crew member is visible, watching them.
Visible crew/equipment: When Roy and Johnny leave Rampart and are heading back in the squad, about 16:40 minutes in, as they are discussing whether Roy has told his wife about house hunting, you can see two signs on the ceiling of the squad's cab. The signs say 'Emergency Saturday 8PM Rehearsal Mark VI Prod'. Possibly they are magnetic signs for the squad doors so people don't mistake the squad for a real fire department vehicle? (00:16:20)
School Days - S2-E14
Other mistake: After the guys rescue Dr. Temple from under the library bookcase, when the attendants take him to the ambulance Johnny alone leaves with him, and while Billy and Roy are still in the library talking we hear the ambulance leaving with its siren blaring, but when the ambulance arrives at Rampart the attendant opens the back door and somehow Billy has actually joined Johnny and Dr. Temple in the ambulance.
The Wedsworth-Townsend Act - S1-E1
Other mistake: At the very start, when the camera moves through Station 10 while the guys are asleep upstairs, we see one of the engines has license plate E111196, but en route there's a closeup of Rescue 10 and its license plate is also E111196.
Revealing mistake: After Station 51 is dispatched to "traffic accident with injuries," when they're on scene at the plant with the injured tanker driver, pay particular attention to the background behind Engine 51 while Roy is on the Biophone with Rampart. When Brackett says, "51, can you give me any more information," we can actually see Station 51 aka 127, directly behind Roy.
School Days - S2-E14
Revealing mistake: While 51's on scene at the traffic accident involving a car that broadsided an ambulance, when Chet opens the back door of the overturned ambulance the license plate reads "99923U" but the "U" is lopsided and pushed to the edge of the plate, which makes it obvious that it's a magnetized letter. It's positioned properly in following shots.
Other mistake: During the structure fire, when Engine 98 rolls up we can see the large red vinyl adhered to the top of the engine's cab. Then, when Truck 106 rolls up we see its company number 106 on the door, but in the overhead shot we can see the number 8 on the roof of the cab, not 106. This presumably means that the door has one of the prop dept's magnetic decals imprinted with 106, and the roof still shows the Truck company's real number.
Transition - S4-E15
Visible crew/equipment: When the three victims of the accident are all in treatment 2 with Morton, in the wide shot just as Brackett, Early, Roy, John, and Gil walk in, at the top of the screen we can see the boom mic dipping down into view.
Visible crew/equipment: Just as 51's guys are removing the novelist from the car that's filled with carbon monoxide fumes, a crew member's reflection, as well as the screen from production equipment, can be seen on the car's driver side window.
Fair Fight - S6-E5
Continuity mistake: When Johnny and Roy are in the ER after the cave-in rescue, while they're talking to Dixie and Brackett, we can see how long Johnny's hair is. After they get back to the station, when the guys decide to name the dog Henry, there's a closeup of Johnny and now his hair is much shorter and even layered at the sides. Additionally, the dirty areas on his shirt change.
Visible crew/equipment: At training center, after 18's guy falls into the trench with the sulfur trioxide, as they're removing his turnout coat just as Roy opens the drug box, seen behind Marco are four crew members who are near the tanker with the sulfur trioxide, past the trench.
Continuity mistake: When Brackett asks Early and Morton to assist with the examination of the hallucinating veteran, in the shot from the hallway the doctors walk into treatment 1, its door has no window, but when it cuts to the shot from inside the room, its door has a window, which means they're all in treatment 2 or 3, not 1.
Continuity mistake: After Squad 51 is dispatched to the 'injured man', when Roy and Johnny get out of the squad, Roy is not wearing his watch as they're walking to the victim while getting hounded by the dog, but in the next shot the watch is back on Roy's wrist as the dog chews on his pants.
Visible crew/equipment: At the scene of the scaffold accident on the side of the building, near the top of the crane, there is a small covered booth that hangs from the crane. We can see the reflection of the hidden second cameraman and his camera in the mirrored windows of the building, as he leans in and out of that booth to film some of the footage we see during this scene.
Visible crew/equipment: When Squad 51 is heading to 1511 West Hill, responding to the attempted suicide, in the closeup of Roy and Johnny en route, we see the reflection of Squad 51 as they're driving past houses/stores on Johnny's side. Just about as Roy says, "It should be it over there," in the reflection we see two crew members riding on the squad - one on top of the squad, and the other one standing on the back.
Other mistake: When John and Roy get back to the station, they head to the kitchen and John takes the hot pot of stew out of the oven with potholders, and when he quickly tries to lift the lid without the potholder, his pain makes it clear that it's burning hot, so he uses the mitt to lift the lid. There's a long metal serving spoon that was left in the stew, and John just lifts it up and starts serving the stew with no problem, even though that spoon should have been too hot to even touch.
Visible crew/equipment: When Roy and Johnny climb up the open drawbridge, just as they reach the top and see the car dangling off the edge, when Roy says "Boy," the second cameraman is visible behind Roy sitting on the bridge.
Visible crew/equipment: When Roy and John are in The Boat with the victim of the explosion, the ambulance arrives and just as it passes by we are able to see a nice reflection of crew members, location set's 9-bank array lighting, reflector screens, a ladder and other equipment.
Other mistake: After finding out about Valerie's three kids, when Johnny and Roy are sitting in the station's locker room at the start of their next shift, there are a few moments during this conversation where Kevin Tighe softly mouths some of Randolph Mantooth's lines as Johnny is speaking, particularly when Johnny says "Beautiful chic."
Visible crew/equipment: When Dixie tells the attendants to wheel Ruthie, the woman who went berserk at the salon, into the treatment room where Dr. Early's waiting, there are two T-marks visible on the floor at Dixie's and Johnny's feet.
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.