Good question superleggera,
But i wonder if sometimes more damage is done when removing the person from the car (especially if its difficult).
In the USA for example, people are so scared of getting sued because they caused the person some more harm by trying to help them, that they do not help AT ALL.
Moving away from the issue of taking some action that will save the persons life, I think even just talking to the person or some kind of physical contant and reassurance can make a big difference.
On the other hand, here are some rescue tools used by the "pros" :
Hydraulic rescue tools - Wikipedia, the free encyclopedia
Usually they cut the A,B or C pillar and peel back the roof to extract the person.
cya
R