"It's not that I love her because I want to make love with her, but I want to make love to her because I love her."
Every time Hideki cries out Chi's name when she is in danger. Combined with the fact that the epic Dark Chi Theme is usually playing in the background you can truly feel how desperately he fears losing her. And the fact that in those tense moments with shady characters lurking, this generally spineless coward fears nothing else.
Chi learned from Mr Ueda that it's not appropriate to hug just anybody, that it should be saved for someone you care about. Later that day, in a personal moment, Chi asks Hideki if it's ok to hug him. Hideki is puzzled since she never asked him this before, but says ok. Chi then hugs him tight as the episode ends.
Chi's "Most precious thing" speech to Hideki when he gets her from Dragonfly's lair.