The group of eleven "sewer ruffians" becoming test subjects in the dream reminds me of survival games where you get a batch of characters. The fact that they have numbers on their clothes (017 for Bai Mu) gives them a dehumanized feel, but their distinct personalities (Matt's grittiness, the gunner's quiet ambition, the gambler's greed, Bai Mu's adaptability) keep them from being interchangeable. I'm interested to see if any of them become obstacles later.