Sicario

Day of the Soldado

This scene:


Now I know why they used that.  It looks cool and badass.  I get that.  Cinematic.

And I am sure the Del Toro character was a bit peeved at the man he was executing, if still outwardly calm.  That might be the definition for the fast mag dump that way.

And I am sure, in a similar sorta thing in real life, enough of those rounds would hit the victim and be enough to probably end his life, satisfying the requirement to assassinate the victim.

But what's your hurry?  Guy isn't going anywhere.  How many of those shots missed completely?  Even at that close range.  The guy is dead, he isn't going to bray about how terrifying it was to be shot with a Beretta in a way that made it seem like a machine gun.

A more carefully aimed 3 shots would be as effective achieving the murder-goal, and be just as fast for a professional, as this character undoubtedly is.  Ok, ok, I'll stop telling hit men and movie makers how to do their jobs.  They don't come to my place of bidness and knock the mop out of my hand.