Hi Wayne,
Sorry to hear about Val's accident, I hope she recovers quickly.
As for dealing with the situation, I know many have said this before, firstly you did exactly the right thing, assessed the situation, reduced your concerns so you could focus on the task in hand and lastly realising the limitations of what you could do because of where you where you called the professionals.
Accidents happen all the time.
Thanks to your actions Val got the best care in the minimum amount of time without the situation becoming more complicated, I reckon that is all any first aider (instructor or not) can hope to achieve.
Best wishes
David