Because the TD uses Windows Media Player to play sounds, this is definitely possible, and a feature I have seriously considered for some time. For the simple fact that, by using an embedded music player to player background music, the TD could conceivably automatically pause, mute, or lower the volume of the music being played when events occur.
But the issues then start around features that users would want added to the music player, and the TD application does enough as it is - it doesn't need to inherit the roles of other, completely distinct applications.
This is on the enhancement list, but I don't see it as important enough to be moved up over other features/additions that would benefit a wider audience.