If one is doing something in public which is normally forbidden, but is permitted because of special circumstances, is he obligated to make it appear not forbidden?
EG: A lunatic threatens to kill your family unless you go into the schul and drink a glass of blood. If you tell people why you are doing it, he will kill them anyway. He is obviously not doing this out of antisemitism because he asks a non-Jew to do a similar task. Should you put some fish scales around so people think you are drinking fish blood?