I don't know who you are addressing with this question, but I'm going to answer it for you. Ishamael was never near the edge of the prison (like Aginor and Balthamel). He was solidly trapped in with the others. That's why the whole "partial trapped" discussion is interesting. I'm saying that as a hero of the horn or servant of the wheel, periodically the Wheel itself would "spin out" Ishamael for various tasks required for the proper turning of fate. It didn't matter that Ishamael was fully imprisoned because the Wheel itself needed him and was able to get him out of jail periodically.