Question: How many lines does Rev-9 have in this movie while in its default form?
Question: Why was John, just before his death, terrified when he saw T-800? The previous T-800 protected him and even there was a bond between them. So, when John saw another T-800, he should have been either sentimental or happy to see the T-800 alive as it should have reminded him of the previous T-800. Why was he scared to see it?
Answer: Because he's not an idiot. He knows Skynet still wants him dead, if it exists, and he knows "his" T-800 was destroyed. Which means if another one suddenly appears in his life, the overwhelming likelihood is that it's another attempt by Skynet to kill him.
Question: If Skynet was prevented from coming online, how did Legion develop the idea for creating terminators?
Answer: Skynet and Legion were both developed for identical purposes: defense network artificial intelligence. It stands to reason they would both evolve in similar ways. Since both Skynet and Legion were fighting a similar human resistance, they both developed similar infiltration units.
Question: When Dani and Grace are in the vehicle that drops out the back of the plane...how then is it possible that the plane is able to nearly come down upon them if it was moving in a forward motion at a great speed in opposite direction? The plane would naturally have gone down miles away from them and not nearly collided with them.
Answer: The simplest answer is, this is a movie, and movies often exaggerate, change, or fabricate details that logically could never occur in real-life. This is a perfect example of a deliberately faked action sequence that is contrived solely to entertain the audience by employing a 'suspension of disbelief.' It's more exciting and suspenseful to be able to see the plane crash, even though, as you point out, it realistically would be miles away by that time.
Question: What happened to the military guy that was injured and left in the Carl's van? Did they simply drop him off the plane along with the van?
Answer: Yes, he dies in the plane crash.
Answer: The T-800 is a metal endoskeleton covered in living human tissue. That human tissue still ages the same way a normal human would. This particular T-800 has been living in the current timeline since the early 1990's so he has aged at least 30 years and originally had the appearance of a roughly 40 year old man.
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