Three roles, one wall
On the bubble, your stack size IS your strategy. The CHIP LEADER holds a subsidized weapon: every fold gains real money, so raise, re-raise, and lean on the middling stacks — but avoid thin spots against the other big stack, whose ladder is as expensive as yours. The MEDIUM stacks are the squeezed: they cannot call the leader light, and waiting bleeds — their lifeline is position, first-in pressure, and picking on stacks shorter than them. The SHORT stacks fight desperation with arithmetic: shove first-in, never call off marginal, and pray two mediums collide. Folding your way onto the ladder is real — but only the short stack gets to enjoy it purely.