$ In the "operate circumstance" you liquidate the portfolio at $t_1$ realising its PnL (let me simplify the notation a tiny bit) In the meantime it's the finish in the working day and time for Trader B to hedge, but he has nothing to delta-hedge because the inventory is 100 https://gregorylquze.suomiblog.com/the-single-best-strategy-to-use-for-pnl-49707483