There are days when I just can't program. We've all had that day, right? If I'm in mental shape to do other work, I do other work. If not, I shut down the machine and go out. (I can't wait until this doesn't require apologizing to my coworkers for taking the day off.)
I think the point is that the idea of professional block is just a fancy name for procrastination. However, I don't think he did any actual research with surgeons, so I can't say whether they procrastinate or not.
At least, any surgeon I'm paying...