Ok...
Tested an incomming call while it was running and no problems
kept right on grooving in the background. Only thing is if you're on a call at the time of warning beeps, you don't get the beeps but that is no big deal as you should be ignoring the calls during the game anyway
You can wait for a break, make a call while it continues to run in the b/g, then come right back in so long as you are careful not to touch the screen and stop the timer. (but i still like the touch option 4tr)