A graphic video (containing a lot of bad language) showing how things develop when a knife gets pulled during a three person grapple (you need to be over 18 and sign in to YouTube to view). Notice how the security guards fail to control one arm which allows the thief to pull his knife. It takes the thief a full 8 seconds (starts at 12 seconds) to pulls the knife and execute the first stab. Also notice how the guy in black was trying to control the arm that eventually stabbed him, but abandoned it.
It is of course very easy for all of us to watch the video and play “Monday morning quarterback”, but nevertheless it is a good illustration of the need to be aware of potential weapons.
All the best,