But she's just a bitch, the cops would tell her to calm down and escort her out to the parking lot. If she refused or directed her tirade at them, cuff her and sit in the back of the cruiser for awhile. A disorderly conduct citation and if she was still not contrite, maybe spend the night in jail.
If Grav did that he'd be a criminal, a terrorist. They'd at least pepper spray or Taser him before a night in jail. And if he looked cross-eyed at them, they'd get some time and a half doing the paperwork for shooting him.
He's wise to the ways of his world, and smart to walk away. Besides, he can come back when they're not looking, piss on the front steps, and run.*
*Not in this weather.