"Mitsuko get in there and get her out, what the hell is going on here?" Ackerman looks around worried about the guests inside.
The water pushed out all the people who standing by the exits, the rest of the guests are in a fast flooding hotel.
The water is rapidly rising and eventually they'll be out of oxygen and that's like 60 seconds away.
Mitsuko finds Yuno swimming just fine to her room.
She's too angry for the water to go down. She's not the one in control and that puts everyone else's life in danger. She side glances at Mitsuko and pushes him back swimming away to open her bedroom window.
The water is too large for her to fix this and the more frustrated she is the more the water keeps flooding. She can turn just a drop of water into a large quantity, but she can only handle a small portion of the large quantity.
That requires total concentration.