The “secondary” insurance is whoever has the 2nd deepest pockets, the primary is the deepest.
If the injury is really bad, the insurance company will try to get out of paying it.
This may be why workers comp is so expensive, it is no fault. Anything short of a deliberate self harm is covered, even if you do something really stupid at no fault to your employer.
How dangerous is being a lawyer/paralegal in an office? One who never has and never will do anything involving criminal or family law, where you get crazies sometimes?
According to what we pay in workers comp, it is slightly safer than being an underwater welder. Just barely.