That is definitely a pool! Empty, but still a pool. He had been warned of this, but it's still incredible to see an entire (enormous!) pool just indoors like this. (He might, surprisingly to himself, be looking forward to when it's full again? It might be nice to go for a swim. And not just for sexy reasons! Just for fun!)
The theatre doesn't have the chairs permanently set up, which he had expected, but, after thinking about it for a moment, this is better. This gives them all kinds of freedom to set the set up in any way they desire -- strip club or airplane or queen's bedroom... he's starting to get hard just thinking about the possibilities, even while still unsettled after their recent, well, conversation. (Did he really nearly lose everything over all this? Well, perhaps he didn't, but it certainly feels that way. All over not telling her the truth about his own desires! It really feels quite stupid now that he thinks about it. He needs to be better for her.) Yes, definitely unsettled, but still getting hard. This place is huge, and has a lot of possibilities, and he is excited to try them out. He plays his flashlight over the place, taking it in as much as he can, before training it on Rosy as she strides towards the stage to open the curtains (he assumes). Yes. A lot of possibilities for sure. (His body agrees.)