My local elementary school has seven different exits from the building and nine different exits from gates. These are the number of exits required by fire regulations for a building of our size. I don’t know how big this specific school was, but most counties will not approve taxes to cover the cost to staff people whose only job is to guard exits. I can tell you that even with 1:1 staffing for students with high needs there are still always opportunities for students to find ways to elope from the premises. It is heartbreaking and awful but nearly impossible to guarantee against in most school settings in the US. My youngest child eloped and attempted to walk home once and got more than a block away - that was with a staff member less than ten feet away from him and following immediately behind him, because he could run fast and move between barriers (like bushes) that the staff member couldn’t fit through. If the staff in this scenario failed to follow protocol, they will be held accountable. It’s just important to remember that sometimes we can do everything right and bad things still happen, and in situations like this the staff who worked the most closely with the child may also be suffering this loss and the guilt and pain of being unable to keep their student safe.