Yeah, he's not super surprised crappy fast food works. That stuff is like drugs to little kids.

"Okay," he replies with a nod. "You wanna stay out here or go in?"

He's noticed Donnie isn't talking and is still acting really cautious. From what he knows about the turtles' upbringing going into a restaurant might be too much to handle, and he damn well isn't going to try dragging him in if he doesn't want to go.