Oh, don't worry, all the best writers do...
(mutilate their characters that is.)
On the tourniquet, as far as I know the reason they advise against it is if the person does it for too long, or too tightly, it can cut off blood supply altogether. But I thought this was when, for instance, the arm is still attached and tissue damage might ensue.
Your medics are very professional, I assume? I also assume they have some sort of field hospital?