You've just been thrown into Cidhna Mine as part of the Forsworn Conspiracy quest. Your weapons and armor have been stripped and you've been left completely vulnerable. Your skills become redundant and you have to play Madanach's game to get out. That is, unless you're a mage. Skyrim makes no attempt to hinder a mage in prison, Cidhna Mine or otherwise, which raises a couple questions.
Is the lack of anti-magic in Skyrim a game oversight? A lore oversight?
What ways might you suggest Bethesda fix this in future ES titles?
Racial powers and dragon shouts are not stunted in Cidhna too. An Orc could Berserk+Elemental Fury or Marked for Death, for example; an Argonian could use his Histskin against Mad. If you have addons you also get access to Soul Tear, Bend Will, Dragon Aspect and the Stone and Black Book powers; if you've beaten the main quest you have the hero summon shout, if you've progressed into the DB questline enough you have the ghost of the assassin; and if you have the Ritual Stone you can first kill all the easy prisoners and then raise them all to fight Mad.
Only a character who depends solely on his gear/consumables for combat prowess would suffer.