From what I understand, pain is an useful mechanism that signals us that something is not quite right with our body (in particular, we're under attack). It's good - it alert us and tells us that we got to do something (stop the threat, or run away, etc). From Wikipedia:
Pain motivates the individual to withdraw from damaging situations, to protect a damaged body part while it heals, and to avoid similar experiences in the future.
However, there are damages that cause too much pain. If you are stabbed in a particular place, you will most likely have so much pain that you simply can't fight back or run away. The shock makes it incredibly hard to do something or even think properly.
So my question is: is there a reason why pain can elevate to such high levels? I'm just assuming that if we had some sort of hard limit on the amount of pain we receive, we could perform better in several dangerous situations. In other words: instead of hurting so much that we can't even think properly, it hurts enough to let us know we are in grave danger but still capable of assess the situation and perhaps even act accordingly.
Obviously some physical damages will render you unable to act anyway. Like, damages on the spine that may cause your limbs to malfunction. But I mean damages such as a large open wound on the abdomen: if that didn't hurt so much, I'd imagine you could probably stand up and run away (you'd probably bleed out but at least you'll have a chance to escape the threat).
My guess is that it "cannot be helped". Pain are signals from different parts of the body to the brain, and once a signal is sent, the brain has no choice but to process it accordingly.