Harley only uses the Joker Toxin when absolutely necessary. And when her life is on the line, she considers it necessary. She gives a side-glance to how Esposito scrambled backwards, and drops back to the floor.

"Good boy. Stay." She grins at him.

Harley reaches for her mallet again, steps pass the laughing guard, and sprints down the hallway towards where she hears the woman screaming.

Sounds like trouble. And hopefully she can solve the issue.