He wrapped her up tightly, but not too tightly in his arms and kissed her temple gently before resting his nose against her. "I'm here," he murmured softly. "I will always be here with you, Syrena. I'm never leaving you again." His words were firm and held a promise that he'd keep until the very end.
They've only known each other a short time, but he knows her well enough to know that she's missing the water, even if her sisters aren't in it. This knowledge is what prompts his slow move towards the water with her, making sure he won't trip or stumble her.