I'm not a medical doctor, but my understanding is that in the scenario of "patient's limb has been trapped/crushed for an extended period and can now be freed" you're supposed to tourniquet off the limb before freeing it.
This helps both for delaying reperfusion issues until the patient can be in the hospital with IV lines in place, and also in case there's an injury which could cause massive blood loss (since a trapped limb is inherently one which is hard to inspect for injuries).
