Macbook Pro Unibody, dvd player makes weird sound

I was playing a DVD in my macbook pro and I noticed that when I tilt the computer at an angle while a dvd is playing it makes a weird sound. take a listen to this and tell me if you've had this problem too.


ps. please no "don't tilt it" responses I've had enough laptops to know they shouldn't do that.

http://www.youtube.com/watch?v=4N1C5MOjqMQ

 

I just tested it out on a fresh cd and YES it does make small scratches on the disc. The sound occurs when I tilt the computer to the left while a disc is spinning. I've owned several laptops and I know they're supposed to hold the discs well enough to prevent this sort of thing. This is replacement #2; the first one had defective speakers, a dented bottom panel, and a loose battery panel; the second had a dented bottom panel, dead pixels, and misaligned battery panel; this one has a misaligned battery panel, a misaligned bottom panel, and a defective optical drive.