that girl thinks she's the queen of the neighborhood (i got news for you! she is!)
For another, she's Sakura's teacher.
Konohmaru probably dove into the city like she did.
Moegi is so surprised she chokes on her own apology, coughs hard, tries to cover her mouth, and loses her balance.
If she tires them out, or they get caught up tagging each other, then she can sneak in, and get a green line on both of their backs before they know she's there.