As armed men smashed their way into a service station, the sole attendant triggered the store's fog cannon.
But it failed to stop the three men, armed with a hammer and golf clubs, making off with an unknown amount of cigarettes and till from the Cambridge Rd, Hamilton, Caltex about 3am today.
Waikato Senior Sergeant Phil Ruddell praised the staff member's actions in setting off the fog cannon and locking himself in the "safe room".
"The attendant did all the right things."
The robbers fled in a white Subaru Forester.