I work for an Orthodox health care professional. I was wondering if the laws of yichud (the prohibition of a man and woman being together in private) apply in the workplace. I am asking because all day long the front door to the office is open and patients come through. However, as soon as the last patient leaves, my employer locks the office door. Is it halachically wrong? If it is wrong, and I suspect it is, is there a respectful way to tell him about this? Any advice that you could pass along would be greatly appreciated.
You're right. If the door is locked, there is a prohibition of yichud, even if both people are religious Jews. Yichud is not so much a matter of suspicion, but rather it is an independent prohibition. The intimacy of being alone together in a private place is reserved only for husband and wife. In fact, part of the marriage ceremony is the cheder yichud, a private room that cannot be entered by anyone else, where the bride and groom go to be alone together for the first time.
As for telling your employer without hurting his feelings, I suggest that you not tell him, but rather ask him about it. For example, you could mention that you were reading a book about the subject and it appeared that your situation is prohibited. You could ask, "Do you know about this issue? It seems pretty easy to avoid; we just leave the door open a little, right?" In the event that he doesn't recognize the problem, you could ask him to do you a favor by asking a rabbi, since you're not comfortable with the possibility of there being yichud.
For sources on the subject I suggest the book "Halichos Bas Yisrael".