This was beautifully written and extremely effectual. Your imagery was exquisite; I was drawn in tight the entire time. And it was so Percy. I loved your characterisation of him. Kingsley, too.
"In that span of seconds, when the rising cage from the depths of the Holding Cells clanked and rocked to a halt, Percy could feel every organ inside his body drop to his knees." -- This is such a fantastic, evocative sentence. I can both see and feel exactly what is going on.
I have to admit, I'm not entirely sure what actually went on regarding Bole/polyjuice, etc, but I can guess. Very interesting and heartbreaking in the end.