PC plans should always be mutable so they can react to unexpected obstacles and setbacks.
Write them in pencil.
Luke: Where have you two been?
Han: We... uh... got lost a bit.
Han: Plan's still good though. We escape on my ship.
R2-D2: How is the plan good? We had one thing to do. One thing.
Han: We rescued Princess! That's a thing.
Leia: Hey! Objectify much?
R2-D2: I'm not leaving without the Orb.
Leia: Okay, go get it, trashbot. You have five minutes before we're out of here.
R2-D2: All right, then. Threepio—
R2-D2: But you have hands!