Marcus: This Hyperion fascist thinks he's safe cause he's got a shield. Spoilers: he isn't.
Cheapskate: It's only a matter of time until Jack burns this city to the ground, you resistance scum!
(If any other than shock weapon is used ...)
Marcus: See how shields resist fire? If you really want to break a shield, you'll need a shock weapon.
(If any other than shock weapon is used again ...)
Marcus: No, no, no -- switch to another weapon and hit him again, da?
(Vault Hunter fires at the target with a shock weapon.)
Marcus: Take that, Jack-lover! A few good hits from a shock weapon will zap a shield away quicker than you can say "buyer's remorse!
(Vault Hunter turns in the mission to Marcus.)