If you keg your beer, it's not a question of IF but WHEN this will happen to you.
NOPE! That's why you ALWAYS check your freshly tapped kegs within an hour(and many times thereafter) of tapping. Anything else will result in fail, as we've seen here.
Anal retentiveness comes in handy, sometimes.
Aside, I would have been bailing that stuff through a coffee filter and praying like crazy, "Please, God. Please save my beer. I promise, I'll never day that word again."