it is a freaking video game
anything is possible
but if we are going to talk realistic
then when i shoot someone, once, more than likely they will be dead or at the very least require a couple of the squad mates to help them.
if they are dead, they don't respawn . EVER
so you pay your money and you die 15 seconds after spawning.
game over
go buy another....realistic
stupidest bs thing i ever heard of talking about a video game