I don't think the presence of sleeping quarters on the ground floor is necessary for this scenario to make sense. I've stayed in that general area. Where I was, there was a freestanding (no A/C or heat) set of bathrooms (men's and women's) by the pool and each had a window. I don't think that's unusual and wouldn't be surprised if they would have been locked after pool hours. Him trying to get in there, to use the restroom or find a sheltered sleeping place after finding himself lost at the wrong hotel, seems to me much more likely than him trying to climb into (or out of) someone's sleeping quarters. From everything that's been presented, it makes the most sense to me that this was nothing more than an unfortunate drunken accident.