Chen's buddy was right there in the car....right there...and she called 911.
People are left in place only where they can't move on their own. Chen was not immobilized....
The paramedics don’t make that determination of whether someone can be moved or not ... until they have examined the situation and have taken into account all the relevant factors.
We don’t go to pimply-faced teenagers, working at a low-paying and dead-end job to get that type of determination ... :-) ...
That’s why 911 is called in the first place.