Sometimes you don't have a choice. It was either risk paralyzing the guy or allowing him to drown on his own blood. The correct thing to in this case is to save his life and worry about the nech injury later.
BTW, in CPR training, they teach you that the very FIRST thing you do after you determine the person is in need of aid is to take charge. Pick someone and tell THEM to call 911. Pick someone else and tell them to go stand on the curb and wait for the ambulance and direct them in. You must take charge or everyone will stand around like a bunch of cattle staring at a new person in their field.
"or everyone will stand around like a bunch of cattle staring at a new person in their field."
Isn't that the truth!