Twilight kept scolding the girls for so long that Pinkie Pie left, unnoticed, and both Rainbow and Rarity took their time to sit on the nearby reef while they were being lectured by their purple friend.

Suddenly, Rainbow noticed that Pinkie Pie was no longer with them. Twilight Sparkle broke her own monologue, turned around and giving credit to Rainbow Dash, looked at Rarity and then up to the surface.
“That girl… is a danger… she might have already turned half the beach by now….Also, Applejack is taking too long to come back with news from either Sunset Shimmer or Fluttershy. What to do? Rarity, please help me keep an eye on Rainbow Dash”
“Sigh… Twilight… I know I did wrong, but really you don’t need to babysit me.”
“No Rainbow, this is not just babysitting you, I need to know that you are no longer a danger for yourself or others. You have already demonstrated that you could not control your emotions. Besides, I think that you and Rarity need to talk about many things”
Rainbow hardens her expression, she knows she did wrong, but she won’t admit it.
“Some friend… Pony Princess”
“What was that?”
“…”
“Sigh… Okay, Rarity, do you think you can handle Rainbow Dash? As far as I have heard, you know martial arts and you could hold the weight of two students and yours, when you were about to fall into Equestria, when my human counterpart became Midnight Sparkle” inquired Twilight.
“Well, yeah, more or less… I guess that fear can bring out the Beast out of the Beauty” said Rarity
“Good, stay here with Rainbow until I have brought Pinkie and Applejack. I hope that Fluttershy has not been infected by this curse and she is still human. With a lot of luck, I would have also met with Sunset Shimmer and my human counterpart. And Rainbow… please, stay out of trouble.”
“Yes, mom” said Rainbow Dash very sarcastically, watching as Twilight Sparkle swam away to the surface.

When she was sure that they were out of Twilight’s ear reach, Rainbow pulled out a beautiful crystal sphere out of the sand, she had just spotted it a few seconds ago.
“So, Rarity, you were saying… you wanted to talk with me, so… you have 10 minutes to tell me whatever you want, before I knock you unconscious with this totally useless crystal ball. But if you convince me with your smooth talk, the ball is yours, it is totally useless, but will be yours.”
Rarity gasped and gulped, she only had one chance to calm Rainbow Dash down…