Continuity mistake: During the scene with the hearse the front right hub cap comes off twice. (00:57:45 - 00:58:35)
Continuity mistake: As the hearse comes out from under the truck while they are trying to get rid of the Terminatrix, you can see that the windscreen is intact. But as they drive down the hill it's missing. (00:59:10)
Continuity mistake: The hubcaps on the hearse come off but are back on in later scenes. (00:59:20 - 01:00:30)
Other mistake: After the T-X is hit by a truck, her primary weapon is damaged and she is seeking a replacement. As she is cycling through available weapons, dummy text is below the weapon name. The text reads: "TEXT regarding the current weapon is being displayed in XP040 weapon sub-window. Important information regarding this weapon is being displayed here." (00:59:52)
Continuity mistake: In the cemetery scene when the Terminator uses a bazooka to fire a missile at the TX, the shot that shows the TX being launched up in the air and hitting a gravestone should have shown the car used by the TX and the road where the car was parked. In the next shot, when the TX gets up and starts to run after the hearse, the road reappears but not the parked car. (01:04:40)
Continuity mistake: When John is threatening to kill himself, his finger alternates from being on the trigger of the handgun to being on the trigger guard from shot to shot. (01:04:55)
Continuity mistake: When the three leads leave the rest area in the mobile home to go find Cate's father, it's about 3.30pm (we hear reference to 6.18 pm and it's in 2 hours 53 minutes). After the conversation where T101 tells that he killed John, you see the car from the outside. You can see on the shadows that the sun is so low, it must be very close to sunset. Shortly afterwards, during the next conversation, it is bright daylight again and it stays so during the rest of the outdoors scenes. (01:08:20)
Revealing mistake: When John, Kate and the Terminator are in the Winnebago, there is a shot that's facing Kate where John says to her that they're going to pull the plug on Skynet and that the bombs won't fall. In this shot, look at John's hair. The green screen is reflected onto it. It is visible throughout the rest of the scene. (01:09:45)
Continuity mistake: When John talks to Catherine while sitting at the table in a moving RV, watch the explosives he is working on. Position of the charges changes with every shot facing Catherine. At one point they completely disappear from the table leaving only the Glock 18 handgun, and just a second later the table shown full of explosives again. (01:09:55)
Continuity mistake: In the scene just after Kate Brewster's dad has been shot he says to go to his office. On the way there you can see his jacket is undone and you can see his shirt and tie. Yet when they enter the office it shows him sitting down with his jacket neatly buttoned up. For a guy who just got shot and is running from machines, I doubt he would worry about buttoning up his jacket. (01:16:40)
Other mistake: When General Brewster tells John and Kate to go to Crystal Peak, Arnie confirms its location as "52 miles north-east, bearing zero-point-five°." Later, when flying the plane, Kate says aloud "all right, oh-one-five°, 52 miles." That's a 10-degree error, for 52 miles, which would put them somewhere in the ballpark of 20-25 miles off-course. (01:17:25 - 01:29:40)
Continuity mistake: When the Terminator is hitting the T-X with the fire extinguisher, she puts her fist up and punctures it so the Terminator chucks it down on the floor. We see it on the floor again, but when the Terminator is running towards the T-X you see where the extinguisher was but now it has vanished. (01:18:55)
Revealing mistake: When Arnie body slams the TX into the toilet, the fact that it's a dummy is blatantly obvious, even at full speed. (01:20:15)
Continuity mistake: When John and Catherine are in the hangar at the runway, the Cessna's tail number is N3035C. When the plane is shown in the air, the number is N3973F. When they land, the tail number has changed back to N3035C. (01:22:25 - 01:25:50)
Continuity mistake: When the Terminator is slamming his fists again the truck trying to fight his new programming, the damage to the truck changes between each camera angle. Watch the passenger front tire collapse under the truck in one scene and then it's just at an angle on the next. (01:28:10)
Continuity mistake: When smashing the truck in the hangar, the T-850 hits it and it falls down so that the bumper is on the floor. When it shows the T-850 from John's POV, the truck is back up on its wheels, although the wheels are still damaged. (01:29:05)
Continuity mistake: When John and the vet arrive at the mountain in their Cessna, the sun casts a shadow straight under the plane. The very moment they walk through the door into the hangar integrated in this mountain (which in the film is immediately after they landed), their shadows are in front of them indicating a low sun. (01:30:45)
Continuity mistake: When John and Kate are in the Crystal peak bunker, T-X smashes through with a helicopter, and there is an external shot of the chopper's rear blade spinning, but when T-X exits, the rear blade is gone, then in the wide shot of T-X it reappears. (01:32:35)
Continuity mistake: JC's leg was crushed by the T-X. After emerging from the elevator, he limps on the wrong leg. (01:36:00 - 01:36:55)
Revealing mistake: At the end of the movie when the missile hits and explodes on the city in the background we see the buildings closer to the screen (the barn and the small office building) get demolished by the shockwave, but all the trees surrounding these buildings don't even move. (01:41:15)
Answer: The difference there would be suicide vs sacrifice. In T2, basically what he meant is he could not commit suicide as it was against his programming. They had beat the T-1000 and had won, but it was too dangerous for Terminator to stick around and knew he had to be destroyed. But he could not purposely do it to himself as it was an act of suicide. However in T3, it was a sacrificial move. The goal of his actions was not to destroy himself, it was to take out the TX and prevent her from reaching John. He had to do this by any means necessary and made a sacrifice play by shoving his core into her mouth and blowing them both up. It wasn't suicide this way, it wasn't self termination. He was taking her out but caused himself to be collateral damage.
Quantom X ★
Also, after watching that scene again, I'm adding this little tidbit. The Terminator didn't actually die from the thing he did to the TX in that move. If you notice towards the end after the nuclear bombs go off, the fall out ash is falling down around its head and its eyes are still on, slowly fading away. It was badly damaged by its move, but the bombs in the end finished him off.
Quantom X ★