Alright... let's blow stuff up!
― Sly responding to Bentley's plan[src]
Clock-La is drawing power from the blimp's engines. To weaken her enough to attack, the gang will need to destroy all four engines. However, one engine is completely locked-down and cannot be entered. So, Bentley tasks Sly with using a TNT barrel to destroy it from the outside.
The payload from the TNT barrel alone is not enough to destroy the engine, so Sly collects three chargers from around Arpeggio's blimp to give the barrel a powerful enough charge. Once he obtains all three, he walks the barrel over to the engine and blows it up.