Notwithstanding any other provision of this code, if a customer has entered a package store during hours in which the package store may sell alcohol and is still in the store at the time the hours of legal sale end, the permittee may allow the customer to remain in the store for a reasonable amount of time to finish shopping, and the permittee may sell an alcoholic beverage to that customer even though the sale occurs after the designated end of the hours of legal sale.
Tex. Alco. Bev. Code § 22.17