There were two ensuite bedrooms in the hotel room Diane and Maya stayed at while in Dubai, so they each got one to themselves.
Christian had purposely reserved this particular suit for two reasons. One, he didn't want his woman to be left alone in a city she hadn't been to before, and given her antisocial nature, he wanted her best friend close to be on the lookout for her.
Secondly, in as much as he wanted the two friends to share a suit, he still wanted that little alone time with Diane so they each got a room apart from the living space included
Though Diane and Maya shared a suite, they still had a little privacy just like now. Christian was being naughty so Diane hid in her room to entertain him.
Diane was putting on a sports bra and matching shorts that barely covered her butt after unpacking her things and freshening up when Christian's request for a video call came in.