While an o.k. movie on it's own, it paled in comparison to the 2nd Terminator movie, and even struggles to complete with the first movie.
If anything, it suffered from not having Mr. Perfectionist, James Cameron directing. Too many things didn't feel right while watching it which causes people like me to think about it too much aftwards finding all the flaws.
Immediately during that sceen a couple things came to mind. #1 - why no skin on the arm? If liquid metal, why would it need to be removed to punch through a seat and flesh? #2 - It's steering, but who is running the Brake and Gas?
I don't think James would have let those slip. And while the story for T3 isn't really pushing the envelope like T2, I think a different director could have turned this from an o.k. movie into one kick *** event.
And note, talk about a downer of an ending. It's been a while since so many innocent people have to die to fulfill a story line. (Swordfish was the last one I can recall in recent time)