Thing is, you don't know until the BG is gone, will he just take the money, or like this POS decide to "leave no witnesses".
That happens to often to take the chance when you have the advantage of surprise.
These thugs think showing a gun gives them the ultimate power, the absolute last thing they expect is for you to pull your own and shoot them.
With some of the whack jobs on the streets today, are you willing to bet your life they will just take the money and leave ?