Discovering a breach where ePHI has been stolen certainly falls into the 'not a good day at work' category. It can be catastrophic for some, especially if the compromise occurred months ago and wasn't detected. Or if a 3rdparty discovered the breach for you, which occurs more often than we think, 47-51% from 2010 -2012 based on the Ponemon Institutes 3rdAnnual Benchmark Study on Patent Privacy and Data Security.
On our list of 9 HIPAA Network Considerations, we are onto topic#8, Breach discovery times: know your discovery tolerance.