Why did Hardenberg surrender so meekly?

I can understand the beginning of the kidnapping when he didn't realize how violent they could be. But, in the cabin, there seemed to be at least one occasion when he could have hidden in the woods and walked to freedom, especially when a frantic Peter couldn't find him. Remember, Peter only had the toy gun. Even before then, when they first arrived and getting out of the bus, you couldn't help but notice that he was more burly than either of the two young men and the rather uncertain Jule.