The energy on the ground was getting smaller and smaller as she managed to redirect most of it to the sky, unfortunately it also meant that she was also electrically charged as part of the thunder energy ran into her (she was removing electrons from the clouds and purring them in the ground after all so she being overly charged with electrons was an obvious result). Her resolve was admirable, even when her skin started burning and her hair stood on end. Even if there were millions of volt running through her body she would survive, she was a homunculus made to manipulate electromagnetism and she could take even more thunder without dying.