Heroic acts in the latest terror attack in London include one woman who saved 20 lives by barricading a restaurant door as terrorists tried to enter and a off-duty police officer who tackled one of the attackers.

The woman was described as “heroic” after she used her body to block the door of a London Bridge area restaurant, reports the Independent UK. The terrorists were then stalled in entering the restaurant and at least 20 people escaped.

The woman blocked the door “for a few seconds,” giving people inside time to escape through the back door of the restaurant, said eyewitness Aksha Patel.

“She knew they were bad people trying to break in,” Patel said. “She managed to hold the door for a few seconds but then I think they overpowered her.”

Another hero in last night’s attack was an off-duty police officer who was one of the first on the scene of the London Bridge attack. He was stabbed after tackling one of the three attackers, according to BBC. The officer is reportedly in critical condition after sustaining knife injuries.

Met Police Commissioner Cressida Dick praised the “extraordinarily brave actions by officers on and off duty first on the scene” who “ran towards the danger.”

On Saturday night, London Metropolitan Police sent out a message via Twitter to tell people what to do while under attack. “Run, Hide, Tell” citizens were urged to do, including barricading themselves and turning their phones off completely.

Seven people were killed and 48 injured in the latest attack. As of Sunday morning, 12 people were arrested, according to BBC News.