There's nothing Eponine loves better than a good dirty joke, and of a Friday night she is often to be heard from all corners of the busy café, cackling with Musichetta over the punchline of a new gag courtesy of Grantaire.
Enjolras, for his part, point blank refuses to see the funny side of such crudeness.
He sits at the table across from Eponine as she smacks the table in mirth, crying with laughter over Grantaire's latest tale of the one-legged man and the healer.
Staring haughtily at the pair of them as they gasp for air, Enjolras wonders aloud how anyone could find such offensive garbage funny. The poor fellow had only one leg, after all, and frankly it was an outrage that such an inexperienced healer could be admitted into a medical establishment in this day and age.
This righteous, matter-of-fact proclamation sets Eponine and 'Taire off on another fit of giggles, and Enjolras sighs in exasperation, wandering off in search of some decent company.
(Later that night when her hiccups have faded away, and she is wrapped tightly around him and snoring lightly, he finally gets the joke, and has to bury his smirk into her hair).