There is a concept in medical care known as "first do no harm." That's the directive to professional medical care providers (doctors, nurses, etc.) and it should apply to us as providers of first aid when we are faced with a medical problem in a survival situation.
Depending upon the type and severity of the injury, there are times when you don't want to move a victim, because if you do you might makes matters worse. And there are other times when you absolutely must move the victim and take your chances on the damage.
For instance, let's say you come upon a terrible car wreck and the driver is trapped inside, hanging upside-down in his seat belt, and unconscious. If you survey the situation and it appears that there is no apparent risk of a fire (fuel isn't leaking, sparks are not flying), you should call 9-1-1 and let the pros handle everything. Don't move the guy. He might have internal injuries, or spinal damage that you can make worse by trying to extricate the victim.
On the other hand, if you come upon the same accident scene and there is fuel spilling and sparks coming from under the hood, you don't have the luxury of waiting 15 or 20 minutes for the EMTs to arrive. You've got to get the unconscious driver out of the car immediately. To leave him there places him as risk of death in a car fire. So you are pretty much committed to getting him out of the car and dragging him out of harm's way, even though technically there is a chance of making his initial injuries worse by doing so.
It's a judgment call that you have to make on the scene. You might be able to wait a little and hope the Paramedics get there quickly, but once you suspect that things are going to go from bad to worse in a hurry, you have to make your move.
In all cases, try to avoid creating more damage or injury. Treat the victim as carefully as the situation will allow. If time permits and the situation allows, stabilize the head and neck in line with the spine, and immobilize limbs before moving the victim.
But if you're dragging the guy out of an active fire, just grab him by the shoulders of his shirt or jacket, cradle his head between your forearms (to keep his head/neck from moving), and drag him away from the danger.
It's a tricky situation, this "first do no harm" stuff. You need to be careful not to increase the injury, but you can't just let the guy perish because you're afraid to do anything to help. Consider taking as many emergency first aid courses as you can, perhaps even qualifying as an Emergency Medical Technician and making yourself available as a volunteer at the local fire and ambulance department. The more education and hands-on experience you have, the better.