Giving Ron a small smile, she offered him a half-hearted wave back. As soon as the door was shut, Rikki lifted her hand and closed her fist, narrowing her eyes with concentration until smoke started to rise from the doorknob, just as she had with Galen's entry. Then, she dropped her hand and looked back at Ron. "Don't touch that," she advised.
At his declaration, Rikki smirked and shrugged. "No, I suppose not, but it's the easiest," she replied. "Here's the thing...I meant it when I asked if you could keep a secret. You can't tell anybody. Not even Hermione or Rose; nobody," she said very seriously, looking Ron right in the eye. "I wouldn't even tell you except that I walked right into it," she tacked on just to let him know how very uncomfortable with sharing she was. "...and because you're my favorite Harry Potter character," she finished with an impish grin.
Rikki took a deep breath and turned her back to Ron, looking down at the swimming pool. "The first thing you should know is how I was going to get you out of the bubble," she thought aloud. Holding out a hand over the edge of the pool, Rikki slowly closed her fist. The pool began to bubble and boil, steam rising up and out of it. Rikki looked over her shoulder at Ron. "I can do a little magic too," she said with a wink. "That's why I asked if it was a regular soap bubble. I could've made it evaporate in a few seconds."
Dropping her hand back to her side, the pool settled as though nothing had happened. She looked back at the pool and paused. That was enough, wasn't it? Ron didn't really need to see the mermaid thing, right? Yeah, no...mermaids weren't good in Ron's world, if she remembered the books correctly. She'd leave it at that. Percy had seen and so had Galen. Ron might be a good ally to have, really, if she let him see, but...the risk of him telling was kind of high given the number of people from his world that were here. His friends; his family.
"Do you play Quidditch no matter what the weather?" she asked, distracted as she went on opening and closing her fist with nerves, watching the pool water boil and settle alternately.