in the scene were john is having trouble trying to start his motorbike in the car park under the gallaria the t-1000 comes out the door and the second he sees john he sprints towards him at full speed but in the scene near the end of the movie wen the t-1000 copies sarah, it pretend to be in pain infront of john and asks john for help, why didint the t-1000 just sprint towards john the way he did in the car park and stick his metal pointy arm straight through johns head, he was standing right infront of him.