I suppose one could attach a harness bar that spanned across the front of the bulkhead. Clearance to the seat may be an issue, but at least the bar would attach to a structural location.
Not knowing the details, in that video it looks to me that the shoulder harnesses slipped out of the 3 bar slide wrap piece. Sadly, a fairly common mistake when not installed correctly.
Scroth instructions:
https://www.schrothracing.com/docs/3-bar-slide-wrap.pdf