Wiktionary
shoot off
vb. (context colloquial English) To leave quickly
Usage examples of "shoot off".
Idahi was so delighted with his present that he immediately began to shoot off the shotgun, a disturbance hardly noticed in the camp of Blue Duck, where a lot of loud activity was going on.
You could shoot off your pistol down there and you couldn't hear it up here.
Like most experienced gunmen, he always left the chamber under the hammer empty when he was doing physical work because, as he had once explained to Matthew, if the hammer should snag on something, a man could shoot off a toe.