Having lots of thoughts about Pei Su and the use of light and shadows throughout the show (mostly half-formed and possibly incoherent), but they wouldn't leave me alone, so here goes.
BEFORE the last hypnosis:
Parts of his face, including one eye, shrouded in shadows (before unveiling the last of the truths still hidden in his mind).
Face bathed in light, when he finally knows the hidden truths (and the source of this particular trauma)
And this is such a contrast to the first scene we see him in the show:
His face almost completely in deep shadows, except his mouth and the tip of his nose. His eyes completely hidden. He's in the dark (blinded to the truth?)
Even when his face has come out into the light, his eyes are still mostly shadowed, and the glasses is leaving sharp streaks of darkness across his face.
There's a lot that could be said here about showing emotion vs stone face, and mask vs mask off