Notice the heart isn’t included. Shooting someone in the heart causes blood loss, perhaps major blood loss. This will leave your attacker with approximately 15 seconds of full voluntary function before being incapacitated. Fifteen seconds is a long time to have someone shooting at you.
I don't know what the OP is basing his knowledge on but I do know that if you shoot someone in the heart they almost immediately lose all will to fight. I imagine some might fight on for a brief period of time, but that would be most unusual and perhaps the individual would have to be highly motivated. I also would not say that someone with a sucking chest wound would have "full voluntary function". Incapacitation start almost immediately, as the person becomes disoriented and is in a great deal of pain.