Leela collides with him (slowly) in mid-air, and starts fake punching.

She moves her mouth quickly, and then speaks, making it look as if she's speaking another language and the English (or everyone's translated languages) are getting dubbed over.

"You'll pay for what you've done, warlord!" She play-acts. "The villages in the countryside will be freed from your iron grasp! Papow!"

Fake slow motion punches!