impulsive

define: impulsive

. (Mech.) Acting momentarily, or by impulse; not continuous.

http://sederet.com/translate.php

in my definition, impulsive is

when two innocent kids blasted off to a lighting shop named fuse, ditched the driver, forgot the brothers,

made the dad going mad. But with silly act, kept doing things that their heart asking to do. 

and, they "...just don't care..." - John Legend