Pulling the trigger a 2nd time is for the movies...
if the gun doesn't go bang when you first pull the trigger... you go into malfunction mode, and you have to train for it.
1. step... get to cover NOW!!!!!!
2. Tap, Rack and Bang... this is not the time to be looking at the gun and wondering if you put a bullet in the chamber, if the mag wasn't seated, etc...
3. if the gun still refuses to go bang... dump mag, clear gun, insert new mag, TAP RACK and BANG... if the gun still isn't working...
Hope your feet are faster than the other guy that's shooting back.
Pulling the trigger a 2nd time? waste of time, rarely have I had a round that didn't go bang the first time go bang when I tried to drop the hammer again... unless you have a bad spring, in that case. fix it.
Just my opinion, others may vary