So I'm even more convinced of Martin's guilt after listening to Ada's interview. It is pretty clear that he tried to make her think that Michele was only trying to wet her hair - even though the tub was half full (who turned off the water when the tub got half full if Michele was unconscious?), and even though Michele was all the way in the tub.
That's the interesting question. Whether she was fully clothed or partially clothed, she clearly didn't intend to get in the tub with some clothing on. So, she was too out of it to avoid getting into the tub with clothes on, but not so out of it to be unable to turn off the water? It just doesn't make any sense.