Even if Arnie had killed anyone prior to the reveal, it would've still been consistent. He didn't have any orders not to do that until later, and the way he too

Even if Arnie had killed anyone prior to the reveal, it would've still been consistent. He didn't have any orders not to do that until later, and the way he took them onboard it seemed clear that the orders were a change to his tactics. Although, seeing who sent him back, it's probably strange they weren't his original orders anyway. I always found the Terminator movies full of that kind of circular weirdness. Anyway for the T2 twist, I always just assumed that when T1 was shot, Arnie was kinda unknown, but by T2 he was a pretty big Hollywood action star and couldn't be the bad guy anymore. So they had to wrangle him being the good guy into a sequel if they wanted him back.