Nevertheless, a doctor did confirm to me the hospital that they, the first only first responders to assist the victims, was located. They were staff of the Gawuna Hospital. This narrowed the search down considerably.
The village of Gawuna isn't identifiable on most maps, the hospital for some reason, is. Here is where the hospital is located, in rural Amhara country. It serves all of the nearby villages.
Eventually, I did manage to speak to eyewitnesses who described the site as a four way intersection near Gawuna. They said it was "near the village of Fela" or at the "Fela Turnabout." Problem is this is an informal name unavailable on any maps. But at least with the description, we could rule out many areas and narrow down the search even more.