If you equate transhuman AI with godlike powers, then it's hard to argue against it escaping. Then again, I bet I could train a dog to keep most humans trapped in a cave, provided I chain them at the opening.

What if the researchers communicating with the AI had no other access to it? What if the physical plant and the administration of the computer systems were off limits to the researchers, and they had no power to release the AI? Furthermore, what if the AI were not allowed to know anything about the researchers? The researchers could be forbidden from revealing anything about themselves to the AI. This would make it impossible for the researchers to publish anything, but let's say that they are working for an organization like the NSA.

It would be really hard for the AI to break out. But it would make for a good science fiction book!