Start the game and wait for the voice to stop talking. Before going through the first portal, take the radio on your table. Carry it with you until you get to the first elevator. Carry it through the particle field and it should get destroyed. Play until chamber four as usual. In chamber four, a radio should be dropped down through the tube with the box. It will end up lying in the pit. Leave it in that chamber, and do not destroy it. Play through chamber five for a strange surprise. Activate the two buttons and the door should open as normal. The radio will be sitting in the center of the floor in the next chamber.