Timeline: Circa 2014. December.
Location: A highway junction in Maine near a road to a town nobody knows about (Fandom is OUAT; it's a season 4 AU. For those familiar with the canon, it's set when the only way to get back to town is with the scroll, which the driver has.)
Situation: A car hit an ice patch, slid across a two-lane highway, and went partway down a ravine before a snowdrift broke its descent. There was a driver, one passenger in the front, one passenger and one caged live chicken in the back. All humans were wearing seatbelts. Both front airbags deployed. The driver is in the worst shape. Airbag caused broken ribs and possibly other injuries (I can be flexible on this). Front passenger is a bit banged up, but nothing serious. Rear passenger is completely unharmed as is the chicken.
Roughly two hours later, two cars approach from the town. They've got winching kits. One driver goes down to hook up the car, the other (with an injured ankle) remains at the top. They're neither of them trained in first aid, but they do have some vague idea that it's bad to try to move accident victims and since if they get them out of the car, they're going to have to scale the ravine holding onto them, they're going to try hauling out the car with passengers inside. At this point, the front passenger realizes that help has arrived and gets out of the car. A moment later, the rear passenger follows. Both can make it to the top on their own, where the other rescuer awaits. At this point an ambulance arrives from the town with two volunteer EMTs. Assume the ambulance is carrying whatever is standard and the EMTs know what they're doing.
Everything goes well until the backseat passenger realizes who's waiting at the top holding out a hand to help her over. She grabs the hand and manages to yank him over the edge and send him hurtling down the ravine. First rescuer sees what's happening and is close enough to leap to intercept. They continue to slide down, until she's able to grasp the trunk of a shrub, stopping their descent, but wrenching her shoulder. So now, we have:
1. One banged-up, bruised older man with a bad ankle. No life-threatening injuries, but not really up for a climb to the top.
2. One thirty-something woman with a wrenched shoulder, a pain in her knee, a lot of bumps and bruises. Not up for a climb.
3. One injured driver in a car with serious injuries. At this point, they don't know how serious. She was conscious when the passengers left, but again, no medical professionals have examined her and they don't know how bad things are.
4. Two EMTs, one ambulance, and a few decisions to make.
What is the order and priority for rescue?
Note: Because of the nature of the canon, and because the accident happened so close to the town line, assume that calling in additional rescue from outside the town is not going to happen. Nobody else is coming along the highway. Help from town is possible, but could not arrive for at least another 20 to 30 minutes. No helicopters.