Harley Quinn

"I hear there's a hostage situation in a bank that needs attention."
"Right, I heard that on the scanner. They're saying it's Harley Quinn. Let's go."

You and Batgirl head off to the bank. You sneak in through a secret roof entrance that she shows you. Inside you see 5 thugs in clown make-up taking orders from a woman dressed head to toe in red in black. "That's Harley." Batgirl whispers to you. "She's most likely doing this as a distraction for the Joker. So don't knock her out, we need to question her."
"Alright. You deal with her, I'll take the armed guards."
"You sure you can take them."
"Yeah."
"Alright, let's go." She drops down and you quickly follow. You use your powers to stop the thugs from firing as you put on a show, pretending to knock them out, when really you're just making them think they need to sleep. Batgirl dispatches Harley nearly as quick after avoiding a few mallet swings she has her on the ground.
"What the hell do you think you're doing messin' up my party B-Girl!? And who's this chump!?" The high pitched New Jersey accent squeals. Batgirl punches her in the face.
"I'll ask the questions Harley. What's The Joker Planning?"
"Kiss my ass Batbrain!" Batgirl punches her again.
"Tell her, Harley." You interupt.
"Okay okay, he's mind controlling an army. He's going to take over the streets while the Big guy's away. He's at warehouse 15 on the docks. The passcode is 579356. Anything else you wanna know?"
"How is controlling them?"
"I don't know, he doesn't tell me nothing!"
Batgirl turns to you, "How did you do that?"
"I can be very persuasive."
"Obviously. How do we deal with this though? If he has an army in that warehouse, we can't just go in and fight them."
"I think I have a plan."