No, they haven't. The dragons weren't eating and Tyrion decided that chained up dragons isn't a good thing and went down there to unchain them. And didn't get fried in the process.
In the book didn't someone go down there to do the same and got killed in the process? I think that scene would have been more powerful had they shown people trying to do the same and getting killed and then Tyrion does it and the dragons don't attack him. But eh, they're on limited time I guess.