ok let me get this right. you are seeing light at the exhaust coming out of the room itself. If so all you would need to do is put in a 90 degree elbow or two inline and the light wont be seen. light wont bend around corners. you will actually be creating a turning corner in your exhaust. im going by your first picture of the room. also you might want to paint the inside of the exhaust tube black nearing the end of it. hope this helps