I haven't. He knows that Yennefer has in terms of burning out her Chaos entirely, but that was what happened instead of being consumed by it. Istredd has always been in very tight control of himself. It's the passionate that have the hardest time finding that. He considers.

The most common way is imbalance, trying to conjure out of nothing. That causes necrosis, it eats you, your skin blackens and dies. It's the first lesson we learn. They use someone as an example. The Brotherhood is very unkind that way. Normally the person only damages a hand and learns the lesson though. You wouldn't be able to do anything for that. It's not something you can reason your way out of, it's a last resort, that would only happen if there was literally nothing left to do.

Someone can burn out using too much of it. You stop thinking about order and control, just the power. It is dangerous, Chaos. It wants to consume, it wants to burn. I've felt some of that before. Istredd will know what it's like when he dances to that edge, and he's always been able to walk back. I think for you it will feel like I'm on fire but I won't care. Not all of this is one hundred percent certain.