Batman's Trust, and International Friendship

Batman had nothing to worry about with a killing machine like this.

Want to run? The moment he thought he had escaped might be when a knife stabbed him in the back.

But Ivan didn't really care. In any case, he had no intention of running.

Batman had restricted his movements to just shy of making him disappear without a sound.

In fact, as long as Ivan reported it in advance, he could wander around America; nobody cared about his daily life.

Besides, why would he run?

He now had resources, a lab, and all sorts of tech support. When he was free, he could go to a bar and talk about life with girls.

More importantly, as long as he was on this team, Tony could only pretend not to see him, even if he knew who he was.

For Ivan, it was the sense of "I like it when you see me but can't do anything about it."

He wasn't an idiot.