Journalist and martial arts expert Geoff Ho faced down three knife-wielding terrorists when they stormed into a bar near London's Borough Market last Saturday.
He could have run away but did not, he told British media, as he was trying to protect his friends and other people hiding at the bar.
In the end, he was stabbed in the neck, but survived the attack.
His actions, and those of others like him who flung chairs and beer bottles at the attackers, have been lauded as acts of heroism and triggered debate on whether bystanders should intervene before security forces arrive.
In Britain, people are advised to "run, hide, tell", during terrorist attacks. Now, some are asking whether they should stay to fight, like Mr Ho and others have done.
Security experts, however, cautioned against taking on armed terrorists, pointing out that escape, if possible, is the best course of action.
In Singapore, the Ministry of Home Affairs (MHA) also advises the public to "run, hide and tell" if there is a terrorist attack. This means to run away from danger, and, if that is not possible, to find cover and stay out of sight. They should contact the police when it is safe to do so.
The advice, said a spokesman for the MHA, was modelled after the British advisory, which was developed based on case studies and real-life testimonies of people who have survived attacks. France also uses a similar protocol, he added.
Experts told The Sunday Times that it is the best course of action in a terror attack.
Dr Damien Cheong from the S. Rajaratnam School of International Studies said that encouraging untrained people to take on armed attackers could lead to greater casualties. "Some guys may think they are Rambo. What happens if they get involved, and as a result, the attacker gets even more agitated?"
But martial arts expert Teo Yew Chye believes people should fight when they are cornered or when escape is not possible."If you can run, you should... (but) you might have no choice but fight, because these terrorists are there to kill you to make a statement," he said.
He therefore prefers the advice of the United States Department of Homeland Security to "run, hide, fight", where fighting is advocated as a last resort in an active shooter incident. He said untrained people can wield everyday objects such as chairs or umbrellas as improvised weapons, and can come together to overpower the attackers.
He cited a 2015 incident, in which a gunman with an AK-47 rifle on a train in Belgium was subdued by three passengers, preventing a possible massacre. Two of the three passengers were US soldiers.
However security expert Kumar Ramakrishna reckons fighting should be an option only if the attacker is alone and lightly armed, and if respondents have martial arts, military or law enforcement training. "If confronted with several attackers who appear well-trained and well-armed as in the Paris attacks of November 2015, the 'run, hide, tell' option appears the most feasible," he said.
Professor David Chan, director of the Singapore Management University's Behavioural Sciences Institute, said the advice to run makes good sense as the "normal human response" of the majority in a terror attack is to flee. People can freeze in situations of extreme fear, which is why it is critical to be reminded of what to do, he added.
The MHA spokesman said "run, hide, tell" is a general advisory to help people stay out of harm's way during an attack."It is a simple and clear message and forms the basic response to most situations. However, when running and hiding are not viable, the public should consider other options available to maximise their chances of survival."
Tampines GRC MP Desmond Choo said that even though the strategy sounds simple, how the population reacts under duress can be uncertain. This is why agencies need to raise awareness in the community.