At first I really thought Umi was acting OOC, being so close like that was something that Nozomi would have done, rather than Umi (imo Umi would just hold hands or sth). But then the artist brought up this idea that when Umi detected serious damage, she became super affectionate to soo Maki, which is both an interesting aspect of the character amd super cute. When I got to the last page, it was clear that showing that part of Umi was the artist's intention. Such care has gone into getting to know these original characters and expanding on their personalities, it's admirable.
Love this.