Could shock cause unconsciousness??
I imagine that she could have had a vasovagal syncope (fainting) from fright (moo). This is where stress / fear cause the vagus nerve to contract and one faints due to sudden drop in blood pressure:
Vasovagal Syncope: Symptoms, Causes and Treatment
But I don't have any guesses on how long that might render one out cold for.
MOO
www.mayoclinic.org
"...causing you to briefly lose consciousness...Recovery after a vasovagal episode generally begins in less than a minute."
Both my sons (teens at the time) have had vasovagal syncopes in the last 5 years, and that tracks with their experiences. One cut his hand mildly deeply with sharp knife in the kitchen, yelled for my husband, they met in the bathroom 5 feet away, and my son's eyes rolled back and he went down. Luckily my husband was able to catch him before his head hit the tub or the tile floor. He was out for about 40 seconds (I was in the doorway when he started to slump). For my other kid, he had it happen when an urgent care doctor was palpating his forearms, which we suspected were broken (yup, both of them were, and it was ulna and radius on both!). His lasted only about 20 seconds.
Nowhere near long enough to slowly bleed out from the kind of neck injury Abby had.