Garnt returned from his time with the kids, while holding their hands seeing they were indeed not strong enough to keep up with his stamina. Guni was the last person who pushed herself to swim with her father, but then she also felt hungry and sleepy. But there was one thing common with all of them. They were happy.
They were happy because they got to spend their time with their beloved father after a long time. On the other hand, Garnt was also satisfied to see all of his family gathered and it created the illusion that everything was perfect for a moment.
[I like it if things stay like this, but obviously, it's not.]
When looking at Guni, Eva was reminded of her own daughter whom she wanted to save, and this renewed her motivation to work harder for everyone's sake.
Notcing that his kids were out of fuel, Garnt knew it was time for him to feed them.