A significant one is when Fujimaru's dad confers his dying words to him via the video feature of a cellphone. Doubles as a Tear Jerker.
Another one is when Fujimaru and Otoya hold off contacting each other when Peter Pan causes a Tokyo-wide blackout that endangers Haruka's ongoing kidney transplant surgery. They know to trust each other to do what needs to be done in their respective locations. Played even more dramatically when the manga presents this moment in parallel panels. This of course leads to a veritable Crowning Moment of Awesome.