I was a paramedic, and it really doesn't matter too much if it is front or back. It is more on where in the front or back. In the ribs area you 'mostly'(mostly meaning there are some space at the top and the bottom this does not include) have your lungs, and of course heart. With most of the area of lungs, you can get shot there and keep going for a few minutes until the lung collapses(pneumothorax or thension pneumothorax) and/or fills with blood.
So as is said before, these things can kill quicker depending on where on the certain organ is it. If it is close or at the point where the artery or vein entrance to the organ the blood loss with impending death will happen sooner.
Average ambulance response time in the US is around 15 minutes. This does not include the time it takes the 911 call taker to answer the phone get the info, put it in the computer, dispatch, police to get there, secure the scene, and allow ems/fire in. This does not include time onscene(its suppose to be <10minutes), time enroute to the hospital(a level 1 hospital) (~10min urban), and time from the ER to the OR(>20 usually)
The time delay I put in there to show how many times the person left the scene alive but dies enroute or at the hospital.
Sorry if it is too gruesome for some
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