First, the non-tower stuff:
To pass it, there must be two people in each small circle, and three people in each large circle. Bound people count towards this total. If everyone is stacked correctly, what this functionally means is that everyone runs out that isn't bound inside the circles. If they're small circles, the two bound people are inside both circles, so they'll live. If there's two large circles, one person runs into both, bringing the total in each to three. If there's one small and one large, one person runs into the outside edge of the large circle, so as to avoid the inner small circle. The small circle has the two bound people, the large circle has those two plus the extra on the edge, so the mechanic is passed.
This is typically handled by having three people marked with numbers 1, 2, and 3, and the player with the lowest number who is unaffected by the bind runs into any large circles while everyone else runs out.