The hero is in the midst of a mission, along with his Five-Man Band and a bunch of Red Shirts. He needs to accomplish some minor and relatively mundane task, which is nevertheless bothersome or unwelcome. So he delegates the job to The Lancer. "Lancer, dig a trench."
The Lancer nods, then turns to The Smart Guy. "Smart Guy, dig a trench."
The Smart Guy nods, then turns to The Big Guy. "Big Guy, [...] [tvtropes.org]