In Terminator 2 we can see the scene, where the T-1000 hits the T-800 with a stick and breaks through T-800 body, damaging the main power supply, which makes T-800 shutdown for a while. After that the T-1000 leaves and starts looking for John Connor again.

In the meanwhile, the T-800 enables the reserve power supply and comes back to life again.

The question is - why didn't the T-1000 anticipate that? He could have made another hit to break the reserve power supply. Surely, since T-1000 was designed by Skynet, it has a thorough knowledge about previous models. If the T-1000 knew the T-800 would survive after such damage, why didn't he make a final blow?

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    I have no canon backup, but I would say it was a matter of weighted priorities; the T-1000's goal was to take out Conner -- the T-800 interfering with that had to be addressed, but no more than was necessary to resume the primary goal. Just as taking out all humans would have prevented them from interfering, but would have distracted from the primary mission, so taking additional steps to ensure the T-800 was out of commission seemed unnecessary. Turns out that's wrong, but in terms of programmed priorities, I can see the logic in the decision.
    – K-H-W
    Commented Jul 2, 2012 at 13:08
  • T-101* - it's called a T-101 not a "T800" and is stated so in the films themselves. Commented Sep 3, 2019 at 11:35
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    @captainobvious, it's a T-800 series, model 101.
    – user118610
    Commented Sep 3, 2019 at 12:40

6 Answers 6


The answer is found in the T2 novelization by Randall Frakes. It seems when the T-1000 destroyed the T-800's power cell it then miscalculated that that was enough and returned to the task of terminating John Connor:

Then it raised the pointed bar again and slammed it down, punching right through, emerging from Terminator’s chest.
And into the floor.
The cyborg was pinioned.

All it could think of was a last futile response.
Strategy nine thousand eighty-five.
Terminator desperately held onto the thought as his head sagged face down and he stopped moving. The light in his eye went out.

The T-1000 looked down at the cyborg and concluded it was no longer a tactical concern. It shifted its attention to its primary target and went off to find it and execute its mission.

In the book it states that the T-1000 begins to malfunction after it is frozen, shattered and then thawed again. This is also shown in the Director's cut of the movie, were the T-1000 begins to lose control of its mimetic ability. This malfunction affects his way of thinking as well.

Furthermore the T-1000 was always a bit of a "wild-card", a dangerous prototype that even Skynet feared. This is stated in the book and in James Cameron's commentary of the movie. Skynet never knew the exact limitations of the unit. Could the T-1000 become sentient and disobedient?

Combining these two clues of a machine that could become sentient and also defective, we can conclude that the T-1000's final battle with the T-800 is fueled more by emotion than tactics. All the punishment the T-1000 throws the 800's way is torturous and like a cat playing with a mouse. We also see the T-1000 waste time, near the end of the film, shaking his finger at Sarah's attempt to knock him into the molten steel. Another 'emotional' reaction.

As for the T-800, having the ability to learn and becoming self aware on purpose (when the Connors flipped the pin-switch of his CPU to read and write mode) he plays dead after his power cell is destroyed.

This was the T-1000's tactical oversight and hubris. The hubris of a free-will malfunctioning super computer. Kinda like Skynet :-)

  1. Skynet knows everything about the T-800 but does the T-1000? Connor sent the T-800 after the T-1000 had been sent back (they had to conquer the time machine before that; if Conner had the time machine first, Skynet couldn't have sent the T1k back). So it seems reasonable that the T1k didn't expect such an opponent.

  2. Are all T-800 built the same? That would seem like a weakness to me which human opponents could exploit. Even if all T-800 were built the same way, is this one? Which past did Connor remember? If he knew that the T1k would waste his T-800, he might have given him an extra power supply. Even if he didn't know, he might have given him an extra anyway because spare parts will be hard to come by in 1995.

  3. What did the T1k know? We (as movie goers) know that the humans didn't have a plan. But for the T1k, this might be a trap to occupy him while Conner gets away.

  4. The T1k might have assessed the damage and come to the conclusion that the T800 is out for 2 minutes. So that would give him 2-3 minutes to look for Conner until it had to return to knock the T800 out once more. Machines never forget; an internal timer would have told him when to return, so this isn't hard to do. Also the T800 was severely damaged, it struggled to stand afterwards. The surprise attack was only possible because of the conveyor belt. So from a tactical point of view, this was a smart move.

  5. It almost worked. If the T800 had come back a few seconds later, if the conveyor belt had failed, if it hadn't one shot left, Connor would be dead.

  6. We know from the third movie that damaged power supplies can blow sky high. Staying could pose a severe risk to the mission. Granted, the T-800 cell is lower yield than the one used in the third movie. But the T-800 displayed great strength which ultimately comes from it's power source.

  7. The primary objective was to kill Connor. The T-800 was just a nuisance in that respect. Conner might try to get away, or prepare a trap, or get reinforcements while the T1k is away.

  8. Lastly, breaking the fourth wall, he had to made a "mistake" somewhere or there couldn't have been a sequel.

I find the "fake mother" much more jarring. It's interesting psychologically but I don't see the tactical advantage at this stage of the fight. The T1k should have just turned his arms into blades and run through John.

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    If we grant #6 and if the T-1000 had knowledge of that (see #1), one would think that the T-1000 might have used that to it's advantage.
    – Xantec
    Commented Jul 3, 2012 at 13:49
  • I would rather use that as an argument not to poke around too much in the insides of the T800 lest it backfires. Or it's proof that the T1k didn't know much because it could just have remove the power cell(s). Commented Jul 3, 2012 at 13:56
  • Point 6 is actually kinda incorrect: T2's Terminator was a T-800, whereas T3's was a T-850 . Both had the 'Model 101' (Arnie) skin, but the 850 had some notable differences in the parts underneath, most notably a) A thicker endoskeleton for combatting plasma weapons and earlier-model reprogrammed bots, and b) The power source, which was switched to a higher capacity (and unstable if broken) hydrogen fuel cell over the T-800's Nuclear Iridium cells.
    – Robotnik
    Commented Apr 22, 2016 at 6:18
  • @Robotnik Good point. I still think that also the "lower capacity" cells can explode violently since T-800 shows a lot of force in combat (which has to come from the power supply). Commented Apr 25, 2016 at 8:52
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    @AaronDigulla not true. Just because a power cell can operate a more powerful engine doesn't mean it is more explosive if damaged. Commented Apr 25, 2016 at 9:21

Unlike the TX, the T1000 does not know the internal state of the T800, it is only processing the same information that we are (e.g. sight, sound etc). Therefore when it massively damages the T800 and the T800 seemed to shut down it had no way of knowing that there was a lucky fluke where the T800 was able to bypass all of the various damaged circuits and repower itself sufficiently to move.

The only way to have been completely sure would have been to obliterate the T800 and the T1000 was busy trying to find John. It was not going to waste time hammering an inferior opponent to bits whilst John got away. The odds of the T800 appearing at exactly the right moment in exactly the right place with a grenade launcher was so remote it was less likely than John escaping as the T1000 wasted time.

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    Fair, but just tearing off the T800 head should not be hard and can be done quickly.
    – sharptooth
    Commented Jul 3, 2012 at 9:47
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    Yeah I guess that is true, I suppose the only real (in universe) answer is that the T1000 made a tactical mistake. He assumed that the damage done was enough and did not see the need for a coup de grace.
    – Stefan
    Commented Jul 3, 2012 at 9:52
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    Removing the head may not have been effective either. In Terminator 3 the Terminatrix nearly decapitates a T-800 and it simply jams its head back on and keeps kicking. Skynet built those 800 series to last.
    – Xantec
    Commented Jul 3, 2012 at 13:47
  • That is true but if the t1000 had ripped the t800 heads off and lobbed it then the chance of the t800 doing anything useful afterwards would be very low.
    – Stefan
    Commented Jul 3, 2012 at 14:26
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    @CodeswithHammer, yes I have read it. The fluke I was referring to was that the massive amount of damage caused did not damage anything important enough to stop the T-850
    – Stefan
    Commented May 18, 2022 at 6:31

We know from the films that we see a clear advancement in SkyNet technology as Judgement Day gets postponed. In T1, when Sarah Connor crushes the first T800 in the hydraulic press, both cells should have been damaged, and there should have been a catastrophic failure. This obviously did not happen. Because Judgement Day was not postponed by this event, technology available to SkyNet did not improve for T2 in the T800.

In the second film, SkyNet knew that that T800 was not enough to stop Sarah Connor, so it sent an advance model back, the T1000. Since the T800 came from the same future as the first Terminator, it's power cells were also not prone to the catastrophic failure. Additionally, the power supply may not have even taken a direct hit. We see from his HUD that he is re-routing power. The primary circuits may have been cut, and the back up circuits needed to be activated. There could also be backup capacitors which would require charging time before the power relay would be completed.

At the end of T2, Judgement day is postponed, and humanity continues to innovate. New technology is available for when SkyNet become self aware in T3. This new technology included much better processing power in modern computer systems, as well as an exponential increase in processing nodes on the internet between the original 1997 J-Day and the 2004 J-day. SkyNet had a better start in the altered future, and could therefore dedicate more resources to developing better technology earlier on in its existence, possibly altering the design of the T800 to include previously unavailable technologies.

This bit is tricky, so please bear with me....

In T3, when the Terminator was explaining the damage to John Connor, he explains that he is powered by two hydrogen fuel cells. This Terminator has two power supplies, so if you allow a little flexibility with the altering of the timelines, there is always the possibility that the T1000 comes from a future where the T800 has two fuel cells, but the T2 Terminator comes from a future where it has only one high capacity battery. If the T1000 knew where to make a direct hit on a T800 with two fuel cells, it is plausible that a design with only one battery would place the power supply elsewhere, rendering such an attack ineffective.


Why do you guys keep referring to the Terminator in T3 as a T-800??? By now any fan of the series should know that was a T-850. And the T-850 was powered by two hydrogen fuel cells unlike the T-800. So the T-800s fuel cell will not blow up like a hydrogen bomb like the T-850 can.

Aside from the power cell difference, the T-850 is upgraded from the T-800. It was designed to be able to withstand plasma attacks, which is why the TX's plasma canon didn't annihilate the T-850. A T-800 or T-1000 would've been killed in one shot.

As for this question, it's obvious that the T-1000 thought it killed the T-800. Assuming that it didn't think that, the T-800 was so badly damaged it thought it wouldn't be a threat anymore.


The T-1000 did make a direct hit. It didn't take into account for the fact that Uncle Bob's CPU was on READ AND WRITE MODE.

The T-1000 also acts more superior to Uncle Bob during their hostile encounter in the mall and the steel mill as it was able to deflect and evade his blows easily. You could say that it was designed to be more human and convincing during infiltration missions to mimic human behavior.

We need to take into consideration that the T-1000 was just a PROTOTYPE model. Which is why it failed. It was unstable and imperfect. It was not a perfected model. It was a test type. More than likely the first of it's kind.

When we're dealing with computers and you make a prototype. Sometimes the Prototype suffers from glitches and bugs in it's software. So when it's hit with Liquid Nitrogen. It must have suffered a severe system crash when it was frozen giving rise to new problems allowing a severely battle damaged Uncle Bob to outsmart it.

We also need to take into account that Uncle Bob was a perfected design from the T-800 series and his CPU was operating on READ AND WRITE MODE. So he learned how to outsmart it.

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    Hi, welcome to SF&F. You should explain clearly how the T-1000 being a prototype affected its decision not to completely disable the T-800. The rest of your answer reads more like a commentary on other answers and some opinion about the sequels, none of which really belongs in an answer. You should explain your point more clearly and clean up the extraneous parts to make this a better answer. Please read How to Answer.
    – DavidW
    Commented Nov 14, 2019 at 19:25

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