Continuity mistake: When Murtaugh and Riggs enter a parking garage to disarm the time bomb in a car's back seat, a No Smoking sign posted on the wall behind Murtaugh becomes obstructed by a vertical pipe and a red warning light between shots. At first the sign is plainly visible, but after Riggs slowly opens the door, the sign's reflection in a window near Murtaugh suddenly reveals the obstructions. (00:03:30)
Continuity mistake: When Delores rams her armored truck into the impostor truck in front of her, its rear bumper becomes noticeably damaged and sags lower. But in subsequent shots, the bumper shows no signs of an impact. (00:11:20 - 00:12:20)
Continuity mistake: During the armored car chase, the bad guys' truck plate number ends "T2" while Delores' plate ends "E4". After Riggs tosses one bad guy out the back and decides to climb onto the outside, the trucks have switched sides with Delores curbside and the bad guy on her left. But two quick close-ups of the trucks bumping together shows Delores' truck is again on the left. (00:13:00)
Continuity mistake: Riggs sees the mugging, and rushes over to intervene. He leaps in, knocks the "mugger" to the ground, and has enough time to comment on the rubber gun before the director shouts "cut." - about 10 seconds. Was the director asleep? (00:22:00)
Audio problem: In the scene where Lorna pulls the history on the MAC-10, the keystrokes aren't even close to being synced with what is appearing on the computer screen. (00:52:40)
Continuity mistake: The scene in the water after our two heroes have been fighting in the boat and Sheriff Dep. boat comes upon them: Notice Riggs's forehead hair - up, down, up, down... and both their hands keeps changing grip on the boat. (01:08:15)
Continuity mistake: When Riggs is following the villains' pickup truck, they make a left turn into a highway and a Delta plane is spotted landing. In the next shot, definitely showing the same turn (note the billboard in the background for "CBS FM" which is in the same place, etc.) the plane changes into an American Airlines plane - note the disappearance of the "Delta" logo and word at the front, and that the Delta plane has a single thin red line, whereas the AA plane has a blue, white, and red stripe along it. (01:28:12)
Continuity mistake: During the chase, an articulated lorry skids. If you look during one of the shots you can see that the trailer part is skidding over skid marks that already exist, obviously from previous takes. (01:28:55)
Continuity mistake: As the villains attempt to flee, they and Riggs drive onto a section of freeway that is being newly constructed. However there are already skid marks on the road surface, which is of course impossible, unless lots of people have screeched to a halt right at the edge of the freeway... (01:29:50)
Visible crew/equipment: As the motorbike falls from the highway, just after it explodes there's a very short wide shot of the site with Danny Glover standing by his car and a couple of guys in hard hats standing around (or running for their life). If you look right behind Danny Glover you can see two people, one in a white hat, one in a red, and one of them is holding a camera - they start moving backwards just before the end of the shot. We then see the bike blowing up, then a close up shot of Danny Glover, from the camera we've just seen. (01:30:25)
Visible crew/equipment: 4 filming or equipment transport trucks can be briefly spotted on the highway above the accident in the chase scene. (01:32:36)
Continuity mistake: Right after Jack's truck exits the subway rail line with a payload of guns, it goes into a skid. Here, the driver is shown wearing sunglasses. But once Jack says "Okay we lost him," the driver now sports his usual pair of glasses. (01:34:35)
Visible crew/equipment: The camera crew is visible in the bed of Jack's truck as it exits the unfinished freeway and barrels through cones and other construction equipment. (01:36:40)
Continuity mistake: In the hockey game, the teams playing are the Los Angeles Kings and the Toronto Maple Leafs. You can notice the real logos when the camera is away from the action. When it gets closer, though (probably because of copyrights), the maple leaf is turned into a spades (from cards) with only "Toronto" written and the Kings' word and crown in the logo become just an "LA" with a slightly different shape.
Continuity mistake: When Riggs runs onto the ice at the hockey game, he collides with two players. After he is hit by the second player, there is a brief shot of Riggs still in the hockey box trying to open the door. This is where he was before he ran onto the ice.
Continuity mistake: When the suspect is shot in the interrogation room, we can clearly see blood on the wall behind him. But when Riggs walks in and sees him, there's no blood visible.
Continuity mistake: In the scene where the bad guys have taken the Captain hostage and are in the garage about to steal the guns, there's a closeup between the Captain & one of the bad guys talking. As the Captain turns, you can see an extra at the back wall dressed as a cop. He leans forward a little like he's supposed to jump in, then backs off. He's not there before or after that.
Continuity mistake: When Riggs is riding the motorcycle chasing the bad guys, the damage to the windscreen of the bike changes as the shot changes from close up to long shots and back. In the close-ups the windscreen is broken in half. In the long shots it is only cracked.
Continuity mistake: In the underground scene, Riggs runs into the tunnel in trainers and come out wearing boots.
Continuity mistake: When Riggs and Murtaugh pull up at the construction site the windows on the car are clear glass, but when they send the car in without a driver the glass is suddenly black.
Answer: She didn't want him to see that she was a fan of those comical idiots. She was supposed to be a tough nonsense internal affairs officer. She was in fact his soulmate, exactly like him, wild and crazy.