I’d call it clever and not a blooper, and there are plenty of real bloopers in that movie. My two favourites:
When Arnie appears in the time bubble, all matter within the two-meter sphere is disintegrated. Interestingly, this takes a corner clean off the back of an 18-wheeler. Even more interestingly, you can see a tidy cross section of the truck’s tires, which continue to hold their shape instead of going flat.
When Arnie commences trashing the biker bar in the opening minutes, a man tries to stab him. If you go frame-by-frame, you can see the rubber knife blade form an “S” shape as it hits Arnie’s body. This can’t be explained away by saying the knife blade bent when it hit Arnie’s metal skeleton, since the next shot shows the knife is still straight.
Well, you can see the hollow openings carved in the sides of the tires, and a rubber knife is handy only if you’re expecting to be attacked by the Three Stooges.
You know, I had never considered that the “third arm” was intentional, since I had seen it listed so many times as a blooper. You guys have made me rethink that.
I never noticed this, while watching the movie, but really, how much more logical do you want it to be? We’ve already seen that this thing can effortlessly assume any shape it wants, including human shapes. It can grow swords out of its arms. It can change direction by inverting, without turning. It can even imitate a linoleum floor. Yet it somehow strains credibility to suppose that it can grow extra arms? Why the heck shouldn’t it?
There’s no “maybe” about it. The extra arms sprout from halfway down the T-1000 torso, and these are the ones used to fly the helicopter. If the arms are from a second person behind Patrick, the second person obviously can’t see anything, and therefore can’t fly a helicopter for real, but if the helicopter is actually on some kind of rig for those shots the only reason for those arms to be there is because Cameron wanted them there.
This is from “Film Flubs: The Sequel” by Bill Givens:
(after citing other “bloopers from T2”)
“We close with our favorite T2 flub: look closely as Robert Patrick chases the police van in the helicopter. A couple of times when he’s using both hands to reload his gun, you see an extra hand sneak out to fly the helicopter. We know he could transform himself, but an extra hand? It’s surely the real-life helicopter pilot.”
After I read that entry, I didn’t know if I could trust this Givens guy and any of his “flubs.” Why? Because I saw the "making of… " special for T2 and have it on tape and Robert Patrick is NOT in a flying helicopter. He’s in a helicopter cockpit being hung from a crane. So no need for a pilot. And it looks as if the effect is intentional and shot so you can see it happening. So, I think it’s not a blooper.