Well, present situation is unique as there has not been invading army/troops to prison before. Casters had kept their spells (what memorized they had) hidden and waited opportunity. Now it's all shit is out as they are now actively executed (warden just told archers to 'kill everyone' order pushes all casters push out all their reserves to survive). Before it was hopeless gloom and strictly organized matter; if you cast spell you were dead.<br/><br/>Now your dead either way, so casters who have memorized spells before prison time (and have left) throw everything they go and it can help push tide as guards/soldiers/warden weren't aware how many casters had spells left. So it's powder keg of magic going off in prison atm. Overall theory is that during prison time you had little to no chance recover or prep spells but you kept spells you had prepared before prison time.