$ While in the "perform scenario" you liquidate the portfolio at $t_1$ realising its PnL (allow me to simplify the notation somewhat) Vega and Theta are sensetivities to volatility and time, respectively, so their contribution could be: Or will it actually not matter? I suggest both equally can return different https://pnl59134.ampblogs.com/pnl-for-dummies-70790494