OAKLAND, CA— Tae kwon do instructor Darryl Connally, 42, said Monday that he never teaches his students everything he knows about self-defense. "I give them enough to get by in most street-level confrontations," said the author of The Nearly Complete Guide To Urban Security. "But you never give a potential opponent an edge." Connally added that "a true master must always be on his guard, lest one of his Basic Women's Self-Defense Seminar pupils rises against him."