I never saw it spelled "sanatarium" before, but apparently that is right or at least used too. "Sanatorium" is what I know. And a website said "sanatarium" in the title, but spelled it "sanitarium" in the text. "Sanitarium" makes more sense too.
It's not that often for me to miss an answer guessed correctly by 90% of the quiz-takers. But somehow my brain decided that "speakers" in the clue for podium should mean loudspeakers and loudspeakers only. Good job, brain!
Similarly, I thought that "stars" projected onto a domed roof meant stars as in celebrities - sort of like a display of a concert projected onto the roof of a building. D'oh! Maybe the clue should better read "domed ceiling", and include planets, too.