If you see someone running from a jewelry (American spelling) store do you really need to think twice about why? This amateur video was shot after the largest jewelry heist in British history. It is a huge story here not just because of the amount of goods that were stolen, but because the robbers had guns. People here tend to pee their pants at the sight of a gun since even the police do not carry them.
Somehow I think if I was strolling around Bond Street, which I love to do, and I saw someone running out of a jewelry store I would assume they were armed and hit the deck. But maybe people here don't realize how far and how fast bullets can travel??