That control has an independent volume control. Invoke it (hold down home button) then as soon as you hear the beep, hit the "down" volume button and set the volume to an acceptable level.
That control has an independent volume control. Invoke it (hold down home button) then as soon as you hear the beep, hit the "down" volume button and set the volume to an acceptable level.
I was going to post the same answer, but when I tried that I wasn't able to turn the volume all the way off. I was able to make it quiet enough that it wouldn't be heard most of the time, but it still wasn't completely silent.