Christian Bale doesn’t like being told what to do. In fact, he admits he’s been more keen to take a role in a film if others tell him not to.

“Some people were saying to me, ‘Why do you want to do that?’ Which made me go, ‘I’m going to go do it, then,’” Bale explains. “I really want to do it more, the more people say that. Maybe I should cut it out.”

The latest film people told him to stay away from is Terminator Salvation, the fourth in the man vs. the machines franchise. Bale steps into the role of John Connor, humanity’s only hope against evil killer robots. At first, Bale wasn’t interested in taking on another big Hollywood franchise.

“Initially when I heard of this I thought, ‘Well, it’s done. There’s no new story to be told,’” he says. “That was why I said no a few times.”

But in the end, Bale agreed, even though the final script hadn’t been written. “I just couldn’t believe that it couldn’t become something that was worthy of people putting down 10 bucks in a movie theatre,” he says.

Though he has a reputation as a sometimes too serious, brooding actor — prone to flare-ups like the tirade infamously leaked online last year from the Terminator Salvation set — Bale actually takes a much more relaxed view of his work.

“This is not Brecht or something. This is Terminator,” he says, cracking a rare smile. “What are people really going there for? They’re going for a good time.”

Of course, offering that kind of a good time requires a decent amount of physical work on an actor’s part. But for Bale, the challenges were limited. “I’ve gone through Batman, and that was tougher,” he explains. “You don’t get humans hand-wrestling terminators. You’ve kind of lost by the time you get to that situation.”

But there were some aspects of the productions he could’ve done without — and not just absentminded crew members.

“When they don’t position the harnesses correctly, it can really hurt … down there,” he deadpans. “You break out in cold sweats.”