I never allow negroes to approach that close to me anymore. If it's unavoidable, my hand is on my concealed sidearm and I make unbroken eye contact.
It shows you really have to be SO aware of your surroundings. I’m guilty of this too...preoccupied with other things.
This is pure hindsight, but a few observations from the photo:
Her body language shows she is relaxed, hands are open, arms are swinging loose. He is tight and erect, arms close to his body. Note the position of his knees: he is slinking along, keeping his center of gravity very low to the ground for balance, ready to turn and pivot. He is far too close for her to turn and run. He is also on the outside of her, blocking off her avenue of escape.
If I saw someone like that, with that body language, there would be at least half a city block between us.