Model: Nash equilibrium in chip EV, 8-handed, blinds 0.5 / 1, BB ante of 1, equal stacks, folded to you. When someone calls, the hand plays heads-up (no multiway). No ICM: on the bubble or at a final table, tighten up. The margin is how much more shoving earns than folding, in BB. In Call mode you are in the big blind facing an all-in, everyone else has folded. ICM mode changes the model: $EV equilibrium with Malmuth-Harville ICM over the remaining stacks, a single caller, and margins are in % of the prize pool.