  For any infinite transitive sofic shift $X$ we construct a reversible
cellular automaton (i.e. an automorphism of the shift $X$) which breaks any
given finite point of the subshift into a finite collection of gliders
traveling into opposing directions. This shows in addition that every infinite
transitive sofic shift has a reversible CA which is sensitive with respect to
all directions. As another application we prove a finitary Ryan's theorem: the
automorphism group aut$(X)$ contains a two-element subset whose centralizer
consists only of shift maps. We also show that in the class of $S$-gap shifts
these results do not extend beyond the sofic case.
