You can if you just practice. Look up drills on tactical and emergency reload. Dry fire practice until you can do it in the dark. Practice indexing. 1.2 seconds is enough to draw and shoot 2 rounds, more than enough time for an emergency reload.
No, you don't understand. I don't carry my spare magazine in an open-top low friction kydex mag holster like IPSC do. My mag pouch is nylon with a spring steel belt clip and a full flap with velcro. I do practice indexing, and I always have my mag on my weak side with the rounds facing the rear so when I draw it I index my index finger along the back of the magazine, then bring it up into my workspace to insert into the gun.
However, I cannot do all of that while trying to hold off the fourth attacker. Each attacker gets one, or maybe two, then reassess. I'm not going to run dry on the first three.