"It's not your fault, you didn't grow up in my world and you don't know me," he says. "But it's so very tempting to try to cross to your plane, let loose, and prove you wrong about what a bad sorcerer I'd be. Except that if I did that I could never go home again or I'd definitely die. Unless I got to epic scale first and your world's momentum translated unproblematically to mine, and I am not at all confident that it would, and there's no testing it except in the doing, which, again, runs a high risk of certain death."