“Smash” without “grab” does simplify the op considerably. Very much hit-and-run.
“Run” can be emphasized by the idea that the mobile defenders realize they’ve been baited and return. You want to clear the area before they come back, but hopefully only after doing enough damage to justify the mission.
Or, if the players feel saucy, I suppose they can insist on ambushing the returning defenders and trying to grab more glory. Depends how the scenario balances the forces. A light raiding force trying to assassinate heavies or worse is the makings of legend, whether legendary glorious wildly unlikely success, or legendary “tales shared in a tavern” “I can’t believe they tried that” failure.