Dissolving guns would likely use wrecking things as a mechanic.
The trip attack does no damage, but it set up Dirk for his next attack so he could use the floor as a club. That did 1-6 damage instead of the 1-4 Dirk would have done with his stolen dagger, or 1-3 from his bare fists. So the guard has 6 hit points or less.
(Scans courtesy of Digital Comic Museum)