We all need to understand our comfort zones for people around us, with knife attacks on the rise, it can get to be critical
In different cultures and even in different setting, the area we subconsciously feel we need for safety and that we feel comfortable with can change. That is not a real problem as long as we understand control space and attack space. For an attacker like a robber or even a rapist they want to be with in 7 feet of us, prior to the attack, so they can get control quickly. Luckily for us most knife wielding attacker's feel the need for a similar distance, perhaps out to 10 feet. But for a successful edged weapon attack on even an armed trained Police Officer 21 feet is within the success zone.
With that knowledge we need to push our security awareness zone out a bit more. The range is different for all of us, but we need to understand the issue.
I took this graphic from the Marine Corp, Combat Hunter training program, but it is a good reference point to work off of.