Second bridge os crash since I bought my air maybe 2 weeks ago, although this time it was while I was on the air programming and listening to music, not while it was sleeping. Wow was that scary! The music stopped, my mouse wasn't responding, and pushing the trackpad wasn't giving any feedback. This lasted a good 10-20 seconds. I had no idea what was even happening until after it rebooted and I checked the error message for, sure enough, mention of the bridge os.
Your scenario sounds exactly like one of my common crash scenarios - programming on XCode and listening to music in the background. Exactly the same behavior as you described.