a guy on the CNN panel said two things would have had to happen for this scenario, and he does not see those two things happening... too much of a coincidence... 1--one of the pilots had to leave the cockpit... 2--the remaining pilot would have to have a medical emergency while the other pilot was away...
statistically, he does not see this happening...
Except that the worst disasters tend to be the result of a string of events — that are often wildly unpredictable.