Re: 10pm.
Hermione was drunk. She hadn't even meant to be! She'd lost track of the time while she was working on her book, and didn't realize until after her first full glass of wine that she hadn't eaten anything. Anything. All day. The wine went straight to her head, and before she knew it, she was incredibly tipsy. She'd started trying to find food to fill her tummy, and found some bread to soak up the wine... but it was too late. She wasn't a very heavy girl, and the alcohol seemed to hit her faster when she hadn't eaten anything in a while.
So she was trying to have fun being drunk and not worry about it. She'd put on some music, and was dancing in the pool area, in her swimsuit. Of course, she was dangerously close to the pool.