A flaw in the take-down and mount

The flaw in a successful take-down like this one is that the person can hold you down and bite you and use pressure-points or allow a friend to attack while your down.  

Kicking Them When Their Down

There's nothing wrong with finishing an attacker off when he or she is down and you know if you don't then they can get up and fight you again.  It's best to not assume that the attacker is seriously done and walk away without thinking they may have a deadly weapon.  All you have to do is stomp-kick or soccer-kick the head once or twice without over doing it then run while watching your back to safety and call the cops.