Even though he's not being left completely without air, the constant give and take has Sora drifting ever closer to light-headedness, which isn't altogether unpleasant -- though you can be sure that Sora does take good advantage of every chance to breathe that he gets. Had Kaito not been pushing things, Sora might have done so himself, the acceleration only feeling natural as the breathlessness increases.

And further into it Sora goes, eyes wide open (figuratively speaking, that is). The simple pleasures have always been an enjoyable pastime but never an ultimate goal and, thus, have always been just as disposable as everything else, in the end. Though he begins to lean a little closer and seem to be willingly going wherever Kaito is taking it, it's not so much falling into Kaito's pace as watching closely and carefully matching it.