Continuity mistake: When Station 51 is being dispatched to the fire and explosion at Martell Industries, the other companies called are Station 36 and Engine 14, but we see Engine 236 at the scene even though they were not called. This is before Captain Stanley asks dispatch for the second alarm.
Continuity mistake: During the fire at Martell Industries, when Roy and Johnny make a mad dash out of the building before the explosions, and midway Roy's helmet falls to the ground as he keeps running, but in the next shot when he and Johnny reach the engine and dive to the ground, the helmet is hanging around Roy's neck.
Continuity mistake: At the start, when Chet tacks the notices up on the bulletin board, the papers are tacked to the board differently between the closeups and wide shots.
Visible crew/equipment: When John and Roy help the driver out of the overturned armored truck, the bulging outline of the mic transmitter is visible on the left side of the driver's shirt, and when Roy's arm is around the man's waist, Roy even puts his palm over the mic transmitter as he bends to pickup the man's gun.
Continuity mistake: During the fire at the chemical plant, the distinctively marked SCBA tanks that Captain Stanley, Johnny and Roy are wearing, when they're searching for the missing man, change when they're inside and then finally exit. Note the different stickers, or lack of stickers, on their tanks.
Other mistake: When Johnny brings the officer who was shot into the ER, as soon as he's loaded onto the gurney Carol takes his BP then tells Brackett his BP, but she also tells him that his pulse is 120, even though she never took his pulse. Additionally, when Morton places the blood vials on the tray and tells the nurse, "I want this sent to the lab STAT, type and cross match, and CBC and differentials STAT," due to the urgency of the situation, but the nurse doesn't leave, she just stands for the rest of the scene.
Revealing mistake: While the squad and engine are en route to "possible fire", one of the camera angles is from the POV behind Roy and John, where the back of squad is located. That’s fine, but the problem is that there's bright sunlight on their backs as they’re driving, when it should not be there. Artistic license is acceptable, but with so much sunlight where it should not be it reveals that Squad 51 is not in its normal state.
Visible crew/equipment: After the ambulance arrives at the lion pit, just as the attendants reach the fence where John and Roy are standing, and the stokes is loaded onto the stretcher, we can see the two white tape marks on the ground, where the zoo employee is standing.
Audio problem: After the sniper throws down the rifle, we see Captain Stanley start talking to Chet and Marco, though at first we don't hear anything, we then hear, "Put on your air masks, " but that is not Captain Stanley's voice we hear. Oddly enough, to me it sounds like John's voice. Have a listen.
Revealing mistake: When Johnny, Roy, Vince, and the wounded officer are hiding between the bakery truck and car, before the multiple bullet holes actually appear on the side of the truck, those areas where the holes will show up have off-color markings, prepared for the stunt.
Visible crew/equipment: After the sniper surrenders, Captain Stanley instructs Engines 12 and 51 to come to the rear of the building, and a few shots later the camera moves alongside Engine 12 as it's turning the corner. In this specific shot, up ahead we are able to see set lighting (including moleeno-style array lights), equipment, crew and actors (in the blue paramedic uniforms), some sitting on chairs in front of the parking attendant's booth (which was shot at by the sniper during the scene).
Continuity mistake: When Johnny and Roy are treating the officer, while hiding between the bakery truck and car, the sniper fires at them which leaves multiple bullet holes on the side of the truck. However, when Vince talks to the Sergeant on the handie-talkie and then fires the tear gas, all the bullet holes on the truck are gone, but they soon reappear.
Visible crew/equipment: After the police officer is shot by the sniper, when Roy and Johnny run with their equipment and duck down behind the squad car, the outlines of the mic transmitter and wire are visible on the back of the Sergeant's shirt, as Johnny and Roy are given flak vests.
Continuity mistake: The window from which the sniper is firing sustains damage with broken glass panes, but then the glass panes are whole and intact, and then they are broken again.
Visible crew/equipment: When Roy and Johnny are with the sick dancer at the bar, the outlines of the mic transmitter and wire are visible on the back of Roy's shirt.
Visible crew/equipment: When Station 51 responds to the photographer who fell in the lion's pit, the outlines of the lav mic transmitters and wires are visible on the backs of Johnny's and Roy's shirts.
Other mistake: When John, Roy, and Vince grab the officer who was shot by the sniper and make a run for it, as they duck behind the car, right behind them we can see a city bus just driving on by the lot, directly in the sniper's line of fire, even though that area's supposedly closed off with heavy police presence.
Continuity mistake: When Gage goes into the lion enclosure you see the lion up high roar with sharp white teeth but the other shots the lion is now an older lion with broken rotten looking teeth.
Continuity mistake: At the lion pit, when John loads the photographer onto the stokes he places the yellow blanket package under her head, and as Captain Stanley, Marco, and Roy lift the stokes out of the pit, we can see that the package is under her head the opposite way.
Continuity mistake: When Dixie gives John a tetanus shot because he fell from a skateboard onto cactus, we know they're all in treatment 1, because when Johnny and Roy are at the open door we can see the door and wall (with fire extinguisher) on the opposite side of the hall, but in the next shot from the hallway he and Roy are leaving treatment 4, which is opposite treatment 3.
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.