What irritates David about the questions the hospital staff keeps asking him while he is waiting for Fellis in "In a Field of Stray Caterpillars"?

David gets turned around in the hospital when he has to search farther and farther for an available bathroom. He is simply trying to find a way to ease his discomfort, but he feels a little lost in the maze, and the staff keeps assuming that he is looking for an exit--a way out. He finds this ridiculous, because the exits are clearly marked and obviously not what he is looking for.