Mike,
So the guy has a really quick jab jab jab.
1) Treat the jab jab jab as one motion. Instead of trying to defend against each individual jab you treat the multiple punches as one technique.
2) You ingnore the multiple punches and zone the legs. Take out the ankle, knee, shin, instep...you must focus practice said targets. As such, the puncher, whose thoughts are on his punching, is unprotected.
3) A weapons master would always use an "extention", a knife, stick, sword, staff, etc. The consequence is clear. The puncher must now examine if he wants to fight at all.
4) A "life master" never fights for sport. His values and beliefs stem from the protection of his family and a belief in a higher power. As such, he must be disciplined in his training using only those techniques that will kill. As such he fights only in one way. When has to fight, he communicates clearly, that he is ready to kill and that he is willing to die.
In this way, even empty handed, the master's hands, feet, and entirety of the body are used only as deadly weapons. As such he prevents the fast multiple puncher from ever throwing the first punch...the consequences for most are not worth the fight.
Mike, some people practice for fun, some for comradery, some for sport, some to uncover truth (kamatuuran). You don't have to practice martial arts to defend against the fast multiple attacker. You simply have to apply what you learn in your every day life. Your successes at work, your time your family, your ability to put food on the table and a roof over their heads...this prosperity is what a life master keeps in mind, in any fight.
Tuhan Joseph