Well for one, the human isn't in a box trying to get out. So an AI mimicking a human isn't going to say weird things like "let me out of this box!" This method is equivalent to writing Hitler a letter asking him a question, and him sending you an answer. That doesn't seem dangerous at all.

Second, I really don't believe Hitler could escape from a box. The AI box experiments suggest a human can do it, but the scenario is very different than a real AI box situation. E.g. no back and forth with the gatekeeper, and the gatekeeper doesn't have to sit there for 2 hours and listen to the AI emotionally abuse him. If Hitler says something mean, the gatekeeper can just turn him off or walk away.