Remember the 'go high'. The 4 members are helping Shinyu to 'go high'. But once he is is the 'high' position, he is not alone because there's Youngjae. Also pay attention in the ending. It looks like Shinyu does not make it although he 'go high', but he is still smiling (maybe because he has 5 members with him). That's my perspective based on my readings from Korean 42s. Basically, the song is about their friendship.