Other mistake: When the crane arm is going through the front of the building with the T-800 on the hook, the final corner column has an explosion and begins to collapse before the arm gets there.
Continuity mistake: The hook for the crane alternates between secured and free between shots. Also, the crane boom switches positions between shots too quickly.
Continuity mistake: When the T-850 tosses John off the hood where he was pinned down, the hood is undamaged. When the 850 started to beat on the truck, it was already damaged before he started.
Continuity mistake: As Catherine grabs a pistol and shouts "Outta my way!", the Terminator stands up, with his left quarter profile towards her. After a cut to her, then back, his position changes to right quarter profile forward. (00:51:05)
Continuity mistake: When John is in the cage Kate threw him in, they hear a crash, and he starts to sit up. The next second, his left arm is suddenly along the side of the cage.
Revealing mistake: When Arnold is breaking a glass cover to a wall display case in the military base, the glass breaks just before his hand touches it.
Continuity mistake: When the TX is driven into the wall at the vet clinic the parked car gets knocked into the gas tanks and there's a massive explosion. A few scenes later the TX drives the crane out of the yard where the gas tanks were. The crane is in pristine condition and showing no damage from the explosion, despite being parked behind the gas tanks.
Continuity mistake: When John, Kate, and the Terminator arrive at the crypt we get a close-up of the memorial plaque. There is a visible seam or crack in the marble that runs behind the plaque and there are no other seams or cracks visible for several inches all around the plaque. Right before the Terminator punches through the marble, you can see that there is now a seam or crack in the marble just above the plaque, and nothing running behind it.
Continuity mistake: When Arnie is carrying the coffin full of weapons from the mausoleum he has the coffin on one shoulder, then in the next shot he is carrying it on the other one.
Continuity mistake: In the scene when the TX, disguised as Kate's fiance, is in a car with the two policemen on their way to find Kate, the TX kills the police officer who is driving by sticking its hand through his chest. His partner sitting in the passenger seat immediately reaches for his gun, causing his seatbelt to slide off his right shoulder. Cut to a shot from behind him and the seatbelt is back on the same shoulder. (00:52:55)
Revealing mistake: During the big fight, the female robot turns her body around to face the male terminator. When she turns around, watch her legs as you can see there is nothing in them. They are just pants with no legs in them.
Continuity mistake: At first, the color of the steering wheel of the police car (the one taking the TX disguised as Kate's fiance) is grey. In a close-up shot of the police officer looking at the TX's arm sticking through his chest, the wheel is now light brown. (00:52:50)
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 ★