1. Go after them and stop them, the fire department will be with them shortly.
2. Buy all the cookies she has to offer.
3. Illegal activity, time to call for police back up.
4. Get into a four-five year long relationship, get her pregnant, and have her accidentally fall of a bridge during her third trimester...
5. Same as 4, no change.
6. Try and see about defending some of the bystanders, bide time for police back up to arrive.
7. Make some arrests, this is a library, for goodness sake's...
8. Try and see if calling the guy's home or friend maybe an option, or else bring it to the police station and wait for somebody to come claim it.
9. Make an arrest.