Out of This World (how do I get past...)

[grover@emunix.emich.edu (Grover Thomas)]

Out of This World:
    I have been stuck on level 5 (xddj) for quite a while.  I have flooded
the cave, gotten across the waterfall/dam, killed a few guards, and shot
down the light, but now I have a problem:  In one room there is a triple-
door, a guard (who is well protected by a force field), and a door behind
him.  If I walk through the triple-door, he shoots me.  If I blow away
the triple-door and put up my own force field, he sends little bouncing
energy-balls across the floor which zap me.  If I jump over the energy-
balls, he shoots me.  Help, how do I get past?
-- 
 __                                                                        __
(__)  Grover Thomas                   InterNet:  grover@emunix.emich.edu  (__)
(__)      "I am the terror that flaps in the night!  I am the"            (__) 
(__)                "stain you just can't rub out. "       -Darkwing Duck (__)