(don't) look up now

So after I taught a lesson this afternoon I decided to go to J&R to look at digital cameras. I want a more powerful one, one that will allow me more latitude. I got on the train at Clark Street, and there, sitting reading, was my shrink. He did not look up, or I would have said hello. There were no seats, so I stood across from him, but a little to the right so I would not be directly in his line of vision. However, there is no way he could not have seen me enter the car, unless he didn't look up from his magazine when the train stopped. Since most people, almost everyone, looks up when people enter the car, he must have seen me. I wonder what he would have done if I had gone and stood directly in front of him. It made me feel bad, in a way, that he wouldn't say hi. Or maybe it is some rule that psychiatrists have: don't acknowledge your patient if you see him on the street (or subway, or bar, or Starbucks, or...)