All did not go smoothly during Free Slurpee day at a Vancouver, Wash., 7-Eleven store.
The Columbian reports that Vancouver police spokeswoman Kim Kapp says about 30 people were inside one of the convenience stores when a male customer threw the icy beverage into an employee's face Thursday afternoon.
Kapp says other customers detained the man until police arrived.
Officers gave the customer a warning and told him to leave. Police say the man wanted to go back inside and apologize but police told him to move along.
No one was injured.
Each year on July 11, 7-Eleven offers free small Slurpee drinks to customers.