Respiratory failure and pulmonary edema are both listed as possible signs of Glyphosate Poisoning (Roundup). I wonder if some of the rooms had bug infestation problems and were sprayed with roundup. Or if something more sinister like poisoning the drinks in the mini-bar is possible?
Products containing glyphosate may cause eye or skin irritation. People who breathed in spray mist from products containing glyphosate felt irritation in their nose and throat. Swallowing products with glyphosate can cause increased saliva, burns in the mouth and throat, nausea, vomiting, and diarrhea. National Pesticide Information Center