My belief here is that the whole concept should be taken even further. After the lights surge and Mace is flung out the window, I think the room should be left in near darkness for the rest of the scene - the lightning having overloaded the electronics and blown out the light bulbs. So you see the reveal illuminated by the lightning, but don't see his deformed face in full until you see him in the Senate. This also adds an extra visual representation that the darkness has descended upon Anakin.