(This is my personal opinion and how I interpreted the lyrics, if you don’t agree then that’s ok :)
Ok so its no secret that Bang and Himchan are close friends (same age). They’ve been sleeping in the same room since predebut. Also since TS arranges the boys by their ages (This is how the ‘golden couples’ were created) they get to share hotel rooms when they promote overseas and they also get free time together. Bang said that Himchan is the person that keeps all members together in B.A.P. Himchan said Bang is B.A.P’s motivation. So you can imagine how important Himchan is to Bang and the other way around.
Come up with your own conclusion but this one is mine. The song fits the whole situation with Himchan perfectly.