Today, I missed the Mincha minyan that is near my college, so I was davening Mincha in the stairwell, which is a relatively quite place. However, there was a security officer who happened to see me standing in the corner and facing the wall and he asked me, “Sir are you all right”? While in the middle of SE, what should I do? What I did is that I nodded politely. Then he told me that I am not allowed to “hang out” in the staircase and that I should go to the “lounge.” I showed him my siddur and nodded politely. I don’t think he understood that I was in the middle of davening. Did I make a Chillul Hashem by acting in a strange way, and what should I do in the future if this happens? Should I carry with me a piece of paper that says, “Please don’t mind me. I am in the middle of praying and cannot talk.” If he continues speaking to me, should I simply walk away and find a different place to finish SE?
It doesn’t seem to be a chillul H-shem since you weren’t doing something that you shouldn’t be doing. Although it is not the normal thing that gentiles do, but you didn’t do anything below standard or wrong. It would be a good idea to have such a sign, just in case something like this happens again. What would be even better for the future is not to daven in a place that you might get disturbed by the security, or by anyone else.