Corrected entry: Why did the T-850 hesitate to shoot the T-X with the grenade launcher before the T-X fatally shoots Brewster? There's no reason why he would hesitate after he shoots her with the automatic weapon since the T-X had already fallen, only to get back up slowly ready to attack again, especially when he already knows that Brewster is one of her targets. This could have been explained if he had been distracted, but he was not.
sidearmsalpha
23rd Feb 2013
Correction: This is a question, not a mistake. The answer is they're basically walking computers, and can only follow their programming. A computer only "knows" what its program is, and can't think for itself.
rswarrior