Out at the launch pad, the igniters are inserted into each engine (in this case, a cluster of a K and four J engines) and attached to the alligator clips that bring the ignition current from the control pad.
Hey, Rocketeer: Your icon reminds me that "Got Fin?" would have been a great t-shirt for the supersonic launch attempts....
The fins shredded right off this rocket as it blasted through the sky. The shock wave at Mach 1 emanates from the nose cone and burns the paint right off the side of the rocket as the pressure wave moves down.