him to the ground. police quickly moving in. the. >> one witness said khan appeared to have two knives, one of them taped to his hand. no one knew at the time that the bomb vest he was wearing was a fake. in the aftermath, london's lord mayor praising the people who took action. >> members of the public didn't realize at the time that was a hoax device and they really are the best of us. another example of the bravery and heroism of ordinary london has running towards danger, risking their own personal safety to try to save others. and i want to say thank you to them on behalf of all londoners but also because it shows the best of us. >> cnn's nick paton walsh recounts for us the terrifying moments as londoners were, again, confronted by terrorism.