People have different ways to show their feelings to their beloved. One of the many ways they reveal themselves and their feelings was through their actions – selfless, serious, and brave actions. These actions would be deemed returned once they were seen or felt, and most of all, accepted. However, there were also actions of endearment that didn't require much attention or notice, therefore, left in a state where they weren't rejected nor accepted.
Donghae had been discreet and silent with his language towards Mando. And it was also because of it that he knew that he couldn't easily do as he wished even if he turned out to have known something more than he was supposed to – in Mando's book. It was the disadvantage of having feelings for someone in silence.
"Why are you here?" Mando asked Donghae.