Jack Hydrazine - great name. It looks to me like one of the combustion chambers let go at the reported 108% thrust.
I’d say either a turbopump, a fuel or oxidizer line, or the nozzle catoed.
Serious question. How can a rocket produce 108% thrust? Isn’t 100% of something the maximum?
Not the mains - I'd think that would be more like an earth-shattering kaboom. Even a nozzle burn-through should be more spectacular and result in some thrust vectoring. Those are rebuilt NK33 engines. That design is based on staged-combustion, with pre-burners powering turbopumps and LOX cooling the bearings. Looks more like the turbomachinery sprung a leak (or blew off some plumbing). This in turn led to a rapid release of O2-rich white hot drive gas. Thus shower of sparks, white-hot flare, no chamber pressure in the mains, and no thrust.
Usually when the hot pressurized RP1 gets loose it's massive fireball time...look for BLEVE on youtube for an example...