Police Tactical Unit officers were squirted with pepper spray - all in the name of charity.
Swapping their blue berets for red Santa hats, trainers and trainees at the unit flexed their muscles on Wednesday for a special mission: raising funds for Operation Santa Claus.
The highlight of the day came when the unit's deputy commandant Ronald Ip Chi-keung announced: "To raise more funds, we have no choice but to mobilise the OC foam."
OC stands for oleoresin capsicum, or pepper spray. The spray causes temporary blindness and burning sensation, and is designed for police use to subdue violent demonstrators.
Ip invited two company commanders to join him in getting sprayed once each in the face by a company member.
It was enough to make the trio's eyes water and their noses run, but they managed to raise about HK$12,000, with each officer at the scene donating HK$30.
"I don't mind because it's to raise funds," Ip said, after rinsing his face with water, his eyes still red. "What else can raise HK$10,000 in one go?"
The experience was almost as unnerving for Christy Fung as it was for her commander. The 24-year-old trainee who sprayed the foam on her commander said: "I was nervous, but it's for charity. I tried not to spray too much."
She explained that each trainer and trainee had been sprayed at least once as part of their training. "We have to know what it feels like when we use it on protesters, so we won't use it recklessly," she said.
"We lead by example," Ip said.
The games day has been held at the unit every year since the 1990s as a team-building exercise and to raise funds for Operation Santa Claus.
The losing teams in each of the six games have to pay a penalty, which goes towards the funds for charity.
One game, the Redman Rumble, saw a member of each of the four teams dressed in a Redman padded combat-training suit with balloons attached. The teams competed to pop their opponents' balloons. Another game involved making a Christmas tree with used bottles and cans.
"We hope to convey the message to our police colleagues and the public through this event that we have the social responsibility to help those in need," said senior inspector Aneka Wong So-fan.
Thanks to the games, together with an auction, charity sale and other donations, the unit raised more than HK$119,000. The money will go towards helping disabled people, children with special needs and others.
Last month, the Police Dog Trial held at Tseung Kwan O Sports Ground raised another HK$100,000 for Operation Santa Claus.